ArticlePDF Available

Effects of forest type and stand structure on coarse woody debris in old-growth rainforest in the Valdivian Andes, south-central Chile

April 2008
Forest Ecology and Management 255(5):1906-1914

DOI:10.1016/j.foreco.2007.12.013

Authors:

Bastienne Schlegel

Instituto Forestal

Pablo Jorge Donoso

Universidad Austral de Chile

Coarse woody debris (CWD) is an important structural and functional component of temperate forests. There are few studies that have estimated CWD biomass in temperate forests of the southern hemisphere. In Chile, this is the first study of CWD in Andean old-growth forests, where tree-fall is the most common type of disturbance and generates a mosaic of different structures within a forest stand, both conditions that must affect the quantity and quality of CWD. We estimated and analyzed CWD biomass in two differing old-growth forest stands, one composed mainly by Nothofagus dombeyi, Laureliopsis philippiana and Saxegothaea conspicua (Nothofagus-dominated stand) and another composed mainly by L. philippiana, S. conspicua and Dasyphyllum diancanthoides (Mixed-species stand). We set up 80 and 95 circular 0.05-ha plots in these stands, where we measured all live trees ≥5cm diameter at breast height (dbh, 1.3m), recorded diameters at the large and small ends of logs and snags, and total length of logs or total height of snags, and classified these within three decay classes. The Nothofagus-dominated forest stand had 88.8Mgha−1 of CWD biomass, compared to 59.6Mgha−1 in the Mixed-species stand, a difference that can be attributed basically to the greater biomass of snags in the former, where most biomass of CWD, logs and snags belonged to N. dombeyi. In both stands we found that most plots had a tree structure dominated by small trees; these plots had greater CWD biomass, of which most was in decay class III, likely reflecting past tree falls that reduced the numbers of large trees and increased CWD. At the stand level the only significant but low correlation occurred between log biomass in decay class III and mean diameter of the plots. However, there were strong relationships of mean diameter (QMD) of the different structural types and log biomass in decay class III in both stands, thus reflecting that diameter structure (or QMD) can be a good predictor of log biomass. CWD biomass in these Valdivian old-growth rainforests is in the range of values found for North Patagonian rainforests sampled with similar plot size, greater than biomass in deciduous forests in North America, and lower than temperate rainforests in the Pacific Northwest in North America, in New Zealand and Tasmania. Differences can be attributed to forest type, forest productivity, and successional phase.

Triangle of structures for irregular forests (from SFFC, 2000; Donoso and Nyland, 2005) for classification of irregular forests into one of seven possible diameter structures in the Nothofagus-dominated and Mixed-species stands. IR, irregular; ST, small trees; MT, medium trees; LT, large trees; MT– ST, medium trees–small trees; ST–LT, small trees–large trees; MT–LT, medium trees–large trees.

…

Boxplot of CWD biomass (Mg ha À1 ) for the Nothofagus-dominated and Mixed-species stands.

…

Relation of log biomass in decay class III, with QMD (cm) (living stand) averaged for each structural type in the Nothofagus-dominated (a) and Mixedspecies (b) stands. IR, irregular; LT, large trees; MT-LT, medium trees-large trees; ST, small trees; ST-LT, small trees-large trees.

…

CWD in old-growth temperate forests of North America and the southern hemisphere

…

stand characteristics, and estimated aboveground biomass (EAGB) and CWD biomass (AES.E.) (maximum and minimum values are given in parentheses) for two old-growth forest stands of the Andean Coigüe-Raulí-Tepa forest type

…

Figures - uploaded by Bastienne Schlegel

Content may be subject to copyright.

Content uploaded by Bastienne Schlegel

Content may be subject to copyright.

Effects of forest type and stand structure on coarse woody

debris in old-growth rainforests in the Valdivian Andes,

south-central Chile

Bastienne C. Schlegel *, Pablo J. Donoso

Insituto de Silvicultura, Facultad de Ciencias Forestales, Universidad Austral de Chile, Casilla 567, Valdivia, Chile

Received 17 April 2007; received in revised form 29 November 2007; accepted 10 December 2007

Abstract

Coarse woody debris (CWD) is an important structural and functional component of temperate forests. There are few studies that have estimated

CWD biomass in temperate forests of the southern hemisphere. In Chile, this is the ﬁrst study of CWD in Andean old-growth forests, where tree-fall

is the most common type of disturbance and generates a mosaic of different structures within a forest stand, both conditions that must affect the

quantity and quality of CWD. We estimated and analyzed CWD biomass in two differing old-growth forest stands, one composed mainly by

Nothofagus dombeyi,Laureliopsis philippiana and Saxegothaea conspicua (Nothofagus-dominated stand) and another composed mainly by L.

philippiana,S. conspicua and Dasyphyllum diancanthoides (Mixed-species stand). We set up 80 and 95 circular 0.05-ha plots in these stands,

where we measured all live trees 5 cm diameter at breast height (dbh, 1.3 m), recorded diameters at the large and small ends of logs and snags, and

total length of logs or total height of snags, and classiﬁed these within three decay classes. The Nothofagus-dominated forest stand had

88.8 Mg ha

1

of CWD biomass, compared to 59.6 Mg ha

1

in the Mixed-species stand, a difference that can be attributed basically to the greater

biomass of snags in the former, where most biomass of CWD, logs and snags belonged to N. dombeyi. In both stands we found that most plots had a

tree structure dominated by small trees; these plots had greater CWD biomass, of which most was in decay class III, likely reﬂecting past tree falls

that reduced the numbers of large trees and increased CWD. At the stand level the only signiﬁcant but low correlation occurred between log

biomass in decay class III and mean diameter of the plots. However, there were strong relationships of mean diameter (QMD) of the different

structural types and log biomass in decay class III in both stands, thus reﬂecting that diameter structure (or QMD) can be a good predictor of log

biomass. CWD biomass in these Valdivian old-growth rainforests is in the range of values found for North Patagonian rainforests sampled with

similar plot size, greater than biomass in deciduous forests in North America, and lower than temperate rainforests in the Paciﬁc Northwest in North

America, in New Zealand and Tasmania. Differences can be attributed to forest type, forest productivity, and successional phase.

Keywords: Nothofagus;Laureliopsis;Saxegothaea; Dead logs; Snags

1. Introduction

Coarse woody debris (CWD) is an important structural

component of many forest ecosystems in temperate forests

(Harmon et al., 1986; Spies et al., 1988; Stewart and Burrows,

1994; Carmona et al., 2002). CWD provides habitat for many

vertebrate and invertebrate species, an important substrate for

plant germination and growth and, a sink and source of

nutrients and carbon that can be recycled within the ecosystem

(Harmon et al., 1986; Hunter, 1990; Donoso, 1993; Takahashi

et al., 2000; Christie and Armesto, 2003). Logs (fallen dead

trees) and snags (standing dead trees) are the major types of

CWD and their relative contribution to total ecosystem biomass

varies greatly in the landscape depending on forest types,

disturbance regimes, topography and stand age (Spies et al.,

1988; Harmon and Hua, 1991; Goebel and Hix, 1996). Harmon

et al. (1986) and Spies et al. (1988) determined that in a forest

chronosequence the amount of CWD follows a U-shaped

pattern, where the maximum stock of CWD occurs following

stand disturbance and in old-growth forests, in the latter due to

small-scale disturbances (mainly tree falls) that generate a new

pulse of CWD input.

Valdivian temperate rainforests (Veblen et al., 1983; Veblen

and Alaback, 1996) in the southern cone of South America are

www.elsevier.com/locate/foreco

vailable online at www.sciencedirect.com

Forest Ecology and Management 255 (2008) 1906–1914

* Corresponding author. Tel.: +56 63 221228; fax: +56 63 221230.

E-mail addresses: bastienneschlegel@uach.cl (B.C. Schlegel),

pdonoso@uach.cl (P.J. Donoso).

doi:10.1016/j.foreco.2007.12.013

highly productive (Donoso, 1989; Armesto et al., 1995), and in

old-growth forests tree-fall gaps are a common type of small-

scale disturbance (Veblen, 1985a,b, 1989; Armesto et al., 1992;

Veblen et al., 1996). This is one reason why these forests should

accumulate large amounts of CWD. Another reason is that the

two major forest types of the region, the evergreen and the

Coigu

¨e–Raulı

´–Tepa (after the common name of its three major

tree species, i.e. Nothofagus dombeyi (Mirb.)–Nothofagus

nervosa ((Phil.) Dim. et Mil.)–Laureliopsis philippiana

((Looser) Schodde)), usually have a high degree of canopy

stratiﬁcation, including emergents among which the most

common species are members of the Nothofagus family

(Veblen et al., 1981; Parada et al., 2003; Donoso and Lusk,

2007).

The only reported study of CWD biomass in Chile (Carmona

et al., 2002) was conducted in old-growth forests of the

evergreen forest, with CWD biomass values similar to those for

standing live tree, and even higher than values found for

coniferous temperate rainforests of the Paciﬁc Northwest of

North America. There is no report of CWD in the Coigu

¨e–

Raulı

´–Tepa forest type, which is simpler in tree species

composition than the evergreen forest type. In this study we

intensively sampled two old-growth forest stands of this forest

type, one strongly stratiﬁed due to the presence of emergent N.

dombeyi trees (Nothofagus-dominated stand) above a canopy

tier of shade-tolerant species, and another comprised only of

shade-tolerant species (Mixed-species). From the point of view

of biomass dynamics in forest ecosystems, the Nothofagus-

dominated forest stand represents a transition phase, and the

Mixed-species forest stand a steady-state phase (sensu Borman

and Likens, 1979) within old-growth forests. The working

hypotheses of this study were that (a) the Nothofagus-

dominated forest stand has greater CWD than the Mixed-

species forest stand, and (b) within each old-growth forest

matrices, patches dominated by small-sized living trees would

have greater CWD due to more recent past disturbances,

particularly tree falls that allowed for CWD accumulation. The

associated objectives were (a) to compare biomass of two old-

growth forests stands in the transition and steady-state phases of

biomass accumulation (with and without an emergent tree

component); (b) to analyze if the current structure and species

composition of live trees can reﬂect the abundance of CWD;

and (c) to compare CWD biomass in these forests with other

temperate old-growth forests of North America and of the

southern hemisphere.

2. Methods

2.1. Study area

The study area is located in the Chilean Andes between 750

and 800 m of elevation in the San Pablo de Tregua experimental

forest (398380S, 728050W) of the Universidad Austral de Chile.

In this region the typical old-growth forests are those of the

Coigu

¨e–Raulı

´–Tepa forest type, which is widespread between

500 and 1000 m a.s.l. in the Andes of south-central Chile,

where either Coigu

¨e(N. dombeyi) or Raulı

´(N. nervosa), or

both, occupy emergent tiers, and the conifer Saxegothaea

conspicua (Lindl.), L. philippiana and Dassyphyllum dia-

canthoides (Less.) occupy the main canopy tier (Burschel et al.,

1976; Veblen et al., 1980, 1981, 2004; Veblen, 1985b; Donoso

et al., 1986; Donoso, 1993).

In this region both large-scale and small-scale disturbances

are common. Large-scale disturbances are caused by volcan-

ism, mass movements triggered by earthquakes, and stand-

devastating windthrow, and generate even-aged forest stands

dominated by Nothofagus species (Veblen and Ashton, 1978;

Veblen, 1985a); small-scale disturbances are those caused by

individual or small-group tree-fall gaps in old-growth forests.

With time the Nothofagus species tend to reduce their numbers

and become only represented by few large trees (LT) in small

numbers. Since frequency of disturbances that allow their

regeneration is shorter than the lifespan of the species, in the

Andes old-growth forest stands usually maintain some live

Nothofagus trees (Veblen and Ashton, 1978; Veblen et al.,

2004). The other species in these forests are more tolerant to

shade, with L. philippiana more tolerant than S. conspicua

(Donoso and Lusk, 2007). These forests can attain a large living

biomass as expressed in large basal area and volume values

(Donoso et al., 1986; Donoso, 1989; Donoso and Lusk, 2007).

Here we studied two old-growth forests of the Coigu

¨e–

Raulı

´–Tepa forest type without evidence of past human

disturbances. One stand is dominated by the emergent N.

dombeyi, and L. philippiana and S. conspicua are the two main

canopy species (Nothofagus-dominated forest). This stand was

established after patchy blowdown by a windstorm (Donoso

and Lusk, 2007), as previously reported by Veblen (1985a) for

forests of this type elsewhere in the region, and had Nothofagus

trees reaching almost 300 cm in dbh (see Donoso and Lusk,

2007), which are likely >500-year old (see Veblen, 1985a).

This is the most common species composition in old-growth

forest stands of this forest type in the Andes of Chile (Burschel

et al., 1976; Veblen et al., 1980, 1981, 2004; Veblen, 1985a,b;

Donoso et al., 1986; Donoso, 1993), although N. nervosa may

also be present with N. dombeyi in emergent positions. The

other stand is dominated by three canopy species, L.

philippiana,S. conspicua and D. diacanthoides, lacks the

emergent Nothofagus, and has a high density of Myrceugenia

planipes ((Hook. et Arn.) Berg) trees in the understory (Mixed-

species forest). This stand has trees of S. conspicua and D.

diacanthoides that reach 250 cm in dbh, and of L. philippiana

that reach 200 cm in dbh, all of which are likely >500-year old

(see Veblen, 1985a). The Nothofagus-dominated stand is in the

transition phase of biomass accumulation described by Borman

and Likens (1979), while the Mixed-species stand is in the

steady-state phase of biomass accumulation (results presented

later show that it has a relatively large amount of coarse woody

debris of N. nervosa while this species is almost absent among

living trees, suggesting that the stand is past the transition

phase). This stand without Nothofagus is rare in the region. We

suggest that it is the result of its south aspect, which apparently

has two consequences: winds coming from the north are

ameliorated, thus preventing the creation of large gaps needed

by Nothofagus to regenerate, and shade-tolerant species (and

B.C. Schlegel, P.J. Donoso / Forest Ecology and Management 255 (2008) 1906–1914 1907

probably also the common Chusquea bamboo) grow twice

faster than in the north aspect (information not published by

Pablo Donoso), so that these species might preempt occupation

of the relatively small-sized gaps by N. dombeyi. Soils are deep

and well-drained and are derived from Pleistocene and recent

volcanic ash layers in a mountainous area of the Andes range

(Tosso, 1985; Veblen, 1985a). A west-coast maritime climate

with a mild temperature range dominates the area, and high

annual precipitations (mainly rainfall) that exceed 5000 mm are

common (Burschel et al., 1976; Veblen, 1985b).

2.2. Sampling plots

In both stands we set up circular plots 0.05 ha in size each,

regularly spaced every 40 m along linear and parallel transects

separated by 40 m from one another. We set up 80 plots in part of

a 62-ha Nothofagus-dominated forest stand, and 95 plots in an

18-ha Mixed-species forest stand. The Nothofagus-dominated

forest stand is located in a terrain with a mean slope of 11% and a

predominant north aspect. The Mixed-species forest stand has a

predominant south aspect with a mean slope of 16%. In each plot,

we measured all live trees 5 cm diameter at breast height (dbh,

1.3 m) or above buttresses in the case of N. dombeyi.We

estimated tree density, basal area, quadratic mean diameter

(QMD) and above-ground biomass of living trees (EAGB) for

both stands. For live trees, EAGB was estimated using species-

speciﬁc equations generated by Gayoso (2001).

We chose this sampling protocol since in a large study on

CWD sampling methods, Woldendorp et al. (2002,2004) found

that in closed forests, plots at least 20 m 20 m in size and in

large numbers were the only means to achieve relatively low

coefﬁcients of variations. However, with the 0.05-ha plots we

used, and the apparently large sampling numbers in each stand,

we still found a very high variation of the data: for the

Nothofagus-dominated and Mixed-species stands the coefﬁ-

cients of variation were 170 and 120% for CWD, 160 and 125%

for logs, and 395 and 216% for snags. To estimate the average

CWD biomass with a sampling error of 30 and 95% conﬁdence,

we would have needed 129 plots in the Nothofagus-dominated

stand and 65 plots in the Mixed-species stand. For log biomass,

ﬁgures would be 114 plots for the Nothofagus-dominated stand

and 69 plots for the Mixed-species stand, and for snag biomass

689 and 205 plots, respectively. Overall, there was a relatively

lower sampling error in the Mixed-species stand, and snag

biomass was more variable than CWD and log biomass.

2.3. Biomass of coarse woody debris

In each plot, all logs on the forest ﬂoor with a stem diameter

20 cm and length 1 m were measured. For each log or branch

deposited on the forest ﬂoor within the limits of the plot we

recorded total length (m), and diameters (cm) at large and small

ends. We identiﬁed logs to species whenever possible. We also

sampled snags, with a diameter at the base 20 cm and height

1 m, in 72 plots of the Nothofagus-dominated stand and in 74

plots of the Mixed-species stand. For each snag we recorded

diameter at the top, diameter at the ground level, total height, and

species whenever possible. These minimum diameter and height/

length considered in this study for recording logs and snags is

based on the methodology utilized by Stewart and Burrows

(1994) in old-growth forests in New Zealand. Similarly,

Woldendorp et al. (2002) measured CWD for a minimum

diameter of 15 cm in Tasmanian old-growth forests, and

considered that samplingsmaller diameters would have increased

the sampling effort signiﬁcantly and could not be justiﬁed in

terms of any additional contributions to the CWD pool.

We calculated the volume of each piece of CWD assuming the

shape of a frustum of a cone (Fraver et al., 2002). Each piece of

CWD was assigned to a three-class classiﬁcation system adapted

from Stone et al. (1998) and Clark et al. (2002): (I) sound, intact

with little evidence of decay, more than 75% of the volume intact

or hard; (II) intermediate, partly ﬁrm, and (III) more than 75% of

the wood soft and rotten, can be kicked into pieces.

Dry biomass was obtained by multiplying the volume of each

piece times the wood speciﬁc gravity (g cm

3

) determined for

CWD in evergreen forests of the Andean range, in Putraique

(398560S, 728270W, 800 m s.n.m.), an area that is dominated by

the same species dominant in the present study site (Gayoso,

2001). We utilized a mean wood gravity of 0.51, 0.36 and

0.25 g cm

3

for the decay classes I, II and III, respectively. These

values are very similar to unpublished values of wood gravity in

ﬁve different species of the sampled forests of the present study,

which were 0.51 g cm

3

for decay class I (range 0.47–0.53 g

3

), 0.29 g cm

3

for decay class II (range 0.27–0.36 g cm

3

and 0.24 g cm

3

for decay class III (range 0.19–0.28 g cm

3

2.4. Diameter structure of plots

To analyze diameter structure and its relation with CWD

biomass, we assigned each plot to a speciﬁc structure class as

speciﬁed in SFFC (2000) and Donoso and Nyland (2005) (Fig. 1).

2.5. Analyses

We calculated species participation in CWD biomass and

EAGB. We compared number of trees per hectare, basal area

per hectare, QMD and EAGB of live trees between both stands

using a Student’s t-test. Since the data of biomass of logs and

snags did not meet the assumptions of normality of error terms

(Lilliefors test) and homocedasticity of variance (Levene test),

and had a skewed distribution (Zar, 1999), we compared their

distributions with the Bootstrap test that does not rely on

theoretical distributions (Diaconis and Efron, 1983). Then, we

analyzed the relation between basal area, QMD, and EAGB of

live trees and biomass of logs and snags with Pearson’s partial

correlation coefﬁcient.

3. Results

3.1. Amount, distribution and species composition of CWD

in both forest stands

The Nothofagus-dominated stand had signiﬁcantly greater

number of trees, basal area, QMD and EAGB (Table 1).

B.C. Schlegel, P.J. Donoso / Forest Ecology and Management 255 (2008) 1906–19141908

Although biomass of CWD and of its components (logs and

snags) was considerably higher in the Nothofagus-dominated

stand, there were no signiﬁcant differences between both forest

stands, which could be a consequence of the large variability of

the data. Boxplots of CWD biomass indicated that both stands

had a similar median and that their frequency distributions of

CWD were skewed. The major difference is that the

Nothofagus-dominated forest has more extreme values (out-

liers) than the Mixed-species forest, which indicates a greater

variability of the sample (Fig. 2).

Biomass of logs and snags was highly concentrated in few

plots (Fig. 3a and b). In the Nothofagus-dominated and in the

Mixed-species stands, 10% of the plots had 49 and 42% of all

the estimated dead log biomass, respectively. Similarly, in the

Nothofagus-dominated stand 75% of the plots did not have any

snag, and only three plots concentrated 78% of the snag

biomass (Fig. 3a), while in the Mixed-species stand 51% of the

plots did not have any snags, and only 12% of the plots

concentrated 71.8% of the snag biomass (Fig. 3b). In the

Mixed-species stand there were proportionally more plots with

snags, but these had a lower biomass because snags had smaller

dimensions (mean diameter of 64 cm and mean height of 5.8 m)

in comparison with snags in the Nothofagus-dominated stand

(mean diameter of 95 cm and mean height of 8.4 m).

The Nothofagus-dominated and Mixed-species stands had a

total CWD biomass of 88.8 and 59.6 Mg ha

1

, respectively,

with relatively similar percentage in decay classes I (16–22%),

II (41–46%) and III (31–34%) (Table 1). While snags

represented 29% of all CWD biomass in the Nothofagus-

dominated stand, they only represented 10% in the Mixed-

species stand. Most log biomass in the Nothofagus-dominated

stand was in decay classes II and III, with 42% in each; in the

Mixed-species stand 46% of the log biomass was in decay class

II, while 32 and 22% were in decay classes III and I. Snag

biomass, however,was markedly different between both stands:

the Nothofagus-dominated stand had a nominal biomass in

decay class III, while the Mixed-species stand had one half of

the snag biomass in this decay class (Table 1).

The proportion between CWD biomass and EAGB of live

canopy trees was 10% in the Nothofagus-dominated stand and

9% in the Mixed-species stand. In the Nothofagus-dominated

stand 65% of CWD biomass and 49% of EAGB was comprised

Fig. 1. Triangle of structures for irregular forests (from SFFC, 2000; Donoso

and Nyland, 2005) for classiﬁcation of irregular forests into one of seven

possible diameter structures in the Nothofagus-dominated and Mixed-species

stands. IR, irregular; ST, small trees; MT, medium trees; LT, large trees; MT–

ST, medium trees–smalltrees; ST–LT, small trees–large trees; MT–LT, medium

trees–large trees.

Table 1

Mean stand characteristics, and estimated aboveground biomass (EAGB) and CWD biomass (S.E.) (maximum and minimum values are given in parentheses) for

two old-growth forest stands of the Andean Coigu

¨e–Raulı

´–Tepa forest type

Variable Nothofagus-dominated Mixed-species

Number of living trees (n ha

1

)

501.5 21.6 (200–1200) a 651.6 27.8 (160–1760) b

BA living trees (m

1

)

125.6 6.0 (31.0–245.8) a 109.4 3.8 (43.4–221.3) b

QMD living trees (cm)

57.3 1.7 (24.9–98.4) a 48.2 1.1 (24.6–81.8) b

EAGB (Mg ha

1

)

877.3 60.1 (153.8–2202.1) a 664.5 27.2 (225.4–1468.0) b

CWD (Mg ha

1

)

(% by classes I, II and III) 88.8 17.2 (0–1061) a (27.9; 41.4; 30.7) 59.6 8.4 (0–301.9) a (20.1; 46.2; 33.7)

Logs (Mg ha

1

)

(% by classes I, II and III) 64.1 11.5 (0–644.8) a (15.8; 41.7; 42.4) 53.7 6.9 (0–295.5) a (21.8; 46.4; 31.8)

Snags (Mg ha

1

)

(% by classes I, II and III) 24.7 11.5 (0–639.3) a (59.2; 40.6; 0.2) 5.9 1.5 (0–72.9) a (4.7; 44.8; 50.5)

Different letters within each row denote statistically signiﬁcant differences between stands (P<0.05), following a Student’s t-test (Zar, 1999).

Same letters within each row denote no statistical differences between both forest stands (P>0.05), following a Bootstrap test (Quinn and Keough, 2002).

Fig. 2. Boxplot of CWD biomass (Mg ha

1

) for the Nothofagus-dominated and

Mixed-species stands.

B.C. Schlegel, P.J. Donoso / Forest Ecology and Management 255 (2008) 1906–1914 1909

by N. dombeyi (Table 2). In the Mixed-species stand, CWD

biomass belonged mainly to L. philippiana,S. conspicua and N.

nervosa, and only 4% of CWD biomass belonged to N.

dombeyi, while EAGB was represented mainly by S. conspicua,

L. philippiana and D. diancanthoides (Table 2).

3.2. Relations between diameter structure of live trees and

CWD

In both stands we found mainly ﬁve types of the diameter

structures described in Fig. 1. Two of the structural types

dominated by medium-sized trees (MT and MT–ST) were not

included in the analysis because they were present only in one

or two plots. In both stands the ST and ST–LT structural types

represented approximately one half of all plots (Table 2). In

these plots most CWD biomass was in decay class III (51% in

the Nothofagus-dominated stand and 43% in the Mixed-species

stand). In the case of log biomass the proportion was the same

in the Mixed-species stand, but in the Nothofagus-dominated

stand 65% of the log biomass was in decay class III.

The only signiﬁcant correlations found in this study were

between log biomass and different dendrometrical variables,

i.e. we did not ﬁnd signiﬁcant correlations in the case of CWD

and snags. Considering all plots in each stand, the only

signiﬁcant correlation in both stands was between biomass of

logs in decay class III and mean diameter (QMD; r=0.25 in

the Mixed-species stand and 0.37 in the Nothofagus-

dominated stand), although the correlation was also relatively

high, but not signiﬁcant, in both stands between log biomass in

class III and QMD in the MT–LT plots (Table 3). By structural

type the only signiﬁcant correlations were found in the

Nothofagus-dominated stand between log biomass in decay

class III and QMD in plots with ST structure (0.51), and

between log biomass and QMD and basal area in plots with

MT–LT structure (0.9 and 0.86).

Considering the mean data per structural type for both forest

stands, we found linear relations between QMD and log-

transformed biomass of logs in decay class III, with an r

Fig. 3. Frequency distribution of log and snag biomass in 80 0.05-ha sample

plots in the Nothofagus-dominated stand (a), and 95 0.05-ha sample plots in

Mixed-species stand (b).

Table 2

Estimated aboveground biomass (EAGB), log and snag biomass, and overall coarse woody debris (CWD, logs and snags) for two old-growth stands in the Valdivian

Andes

Species EAGB Log Snag CWD

(Mg ha

1

) (%) (Mg ha

1

) (%) (Mg ha

1

) (%) (Mg ha

1

) (%)

Nothofagus-dominated

N. dombeyi 431.4 48.8 35.2 54.8 22.8 92.3 58.0 65.3

L. philippiana 148.5 17.0 4.5 6.9 0.9 3.8 5.4 6.1

S. conspicua 270.1 31.1 4.6 7.2 0.9 3.7 5.5 6.2

D. diacanthoides 26.6 3.1 – – – – – -

A. luma 0.7 0.1 –– – – – – –

n.i. – – 19.9 31.0 0.1 0.2 19.9 22.4

Total 877.3 100.0 64.1 100.0 24.7 100.0 88.8 100.0

Mixed-species

N. dombeyi – – 1.8 3.3 0.6 10.2 2.4 4.0

L. philippiana 203.2 30.5 11.4 21.3 4.3 71.6 15.6 26.3

S. conspicua 261.5 39.3 13.6 25.4 0.8 13.8 14.4 24.3

D. diacanthoides 178.9 26.9 4.9 9.2 0.2 3.7 5.2 8.7

N. alpina 1.9 0.3 10.4 19.4 – – 10.4 17.5

M. planipes 18.5 2.8 0.04 0.1 0.04 0.6 0.04 0.1

A. luma 1.7 0.3 – – – – – –

n.i. – – 11.4 21.3 – – 11.4 19.1

Total 665.8 100.0 53.5 100.0 5.9 100.0 59.4 100.0

n.i., specie not identiﬁed.

B.C. Schlegel, P.J. Donoso / Forest Ecology and Management 255 (2008) 1906–19141910

0.86 in the Mixed-species, and 0.93 in the Nothofagus-

dominated stand (Fig. 4). These relations indicate that plots

dominated by small trees (ST), which had a lower QMD, had a

higher biomass of logs in decay class III. In contrast, plots

dominated by LT and a combination of medium and large trees

(MT–LT), which had a higher QMD, had the lowest biomass of

logs in decay class III. The slope of these relationships was

steeper in the case of the Mixed-species forest, in which log

biomass was slightly lower in every structural type, but three

times lower in the MT–LT plots. We did not ﬁnd signiﬁcant

relations between biomass, by structural type, of decay classes I

and II and basal area or QMD, or between snag biomass,

averaged by type of structure, and basal area or QMD.

4. Discussion

4.1. CWD in Andean old-growth forest stands of

contrasting structure and composition

We have estimated CWD in two Andean forest stands that

differ basically in the presence or absence of the emergent N.

dombeyi component. Therefore our results allow comparison of

the two stands but extrapolation to the two forest types must be

cautious since we did not have replicates of stands of each forest

type, i.e. we lacked a measure of variance among different

stands of each type. However, the Nothofagus-dominated stand

is typical of old-growth forests in the Andes in its composition,

structure and basal area (Burschel et al., 1976; Veblen et al.,

1980, 1981, 2004; Veblen, 1985a; Donoso et al., 1986; Donoso,

1993), so that we can suggest that this stand (and likely the less

common Mixed-species stand) represents well common

conditions of CWD biomass expected to ﬁnd in these forests

in the region.

Both stands had a great variability of CWD biomass

distribution in the plots, which reﬂects the gap-phase dynamics

that predominates in these forests (Veblen, 1985a; Donoso and

Lusk, 2007), and is consistent with general patterns of CWD

distribution both at the stand and the forest levels (Lo

˜hmus

et al., 2005; Woldendorp et al., 2002, 2004). In both forest

stands CWD biomass represented about 10% of the estimated

aboveground biomass (EAGB) (Table 1), but while EAGB was

32% greater in the Nothofagus-dominated stand, CWD biomass

was almost 50% greater (the latter a difference that was not

signiﬁcant due to the great variation of the data), suggesting that

old-growth stands in a transition phase (sensu Borman and

Likens, 1979) have not only a greater EAGB than those in a

steady-state phase but also a greater CWD biomass. In this

stand with emergent N. dombeyi there was a much greater

relative proportion of snags (28% of the total CWD biomass

compared to only 10% in the Mixed-species stand; Table 1) due

basically to the large biomass in large snags of N. dombeyi

(Table 2), which is a consequence of the dominant type of wind

damage on this species: most N. dombeyi trees damaged by

wind in San Pablo de Tregua are wind-snapped (57%) rather

than uprooted, while in the Mixed-species stand the species

most damaged by wind is S. conspicua and it is most commonly

Table 3

Pearson correlation coefﬁcients between log biomass and basal area (BA), and

between log biomass and quadratic stand diameter (QMD), for the two stands

studied according to structural types based in the relative importance of small,

medium and large trees

Structure

Variable Nothofagus-

dominated

Mixed-species

Nln(biomass)

(Mg ha

1

)

Nln(biomass)

(Mg ha

1

)

III

Total

III

Total

IR BA (m

1

)110.02 0.08 19 0.01 0.02

QMD (cm) 11 0.48 0.11 19 0.24 0.01

LT BA (m

1

) 18 0.14 0.55

24 0.28 0.25

QMD (cm) 18 0.06 0.21 24 0.09 0.12

MT–LT BA (m

1

)70.67 0.86

4 0.21 0.26

QMD (cm) 7 0.67 0.90

40.54 0.14

ST BA (m

1

)160.29 0.12 21 0.24 0.06

QMD (cm) 16 0.51

0.33 21 0.06 0.04

ST–LT BA (m

1

) 25 0.06 0.04 26 0.01 0.03

QMD (cm) 25 0.22 0.19 26 0.22 0.26

All structures BA (m

1

)800.18 0.04 95 0.08 0.06

QMD (cm) 80 0.37

0.25

95 0.26

0.12

The different types of structures (IR, LT, MT–LT, ST and ST–LT) are

speciﬁed in Table 1.

Biomass in decay class III.

Total biomass (sum of three decay classes). BA, basal area; QMD, quadratic

mean diameter.

Signiﬁcance level P<0.05.

Fig. 4. Relation of log biomass in decay class III, with QMD (cm) (living stand)

averaged for each structural type in the Nothofagus-dominated (a) and Mixed-

species (b) stands. IR, irregular; LT, large trees; MT–LT, medium trees–large

trees; ST, small trees; ST–LT, small trees–large trees.

B.C. Schlegel, P.J. Donoso / Forest Ecology and Management 255 (2008) 1906–1914 1911

uprooted (50%) rather than wind-snapped (Veblen, 1985a). The

ﬁeld data conﬁrms this pattern: 40% of the CWD biomass of N.

dombeyi was in snags, and 60% in logs, compared to 84 and

16% in the case of S. conspicua in the Nothofagus-dominated

stand, and 94 and 6% in the Mixed-species stand. Overall, we

suggest that (a) transition forests have greater biomass than

steady-state forests both in the EAGB and the CWD biomass,

and (b) CWD in transition forests has a greater proportion of

snags relative to older forests due to the fact that pioneer species

seem to be less likely to be uprooted when damaged by wind, as

also observed by Tyrrel and Crow (1994) in Hemlock-

hardwood forests in the USA. These results suggest that the

model proposed by Spies et al. (1988) and supported by

Carmona et al. (2002) showing the greatest values of CWD

biomass in older forests could be modiﬁed to illustrate that

forests in a transition phase accumulate greater CWD biomass.

A sampling of several replicates of each forest type would be

needed to support this suggestion.

4.2. Diameter structures and CWD biomass

Estimations of CWD biomass and carbon can be determined

from other stand data (Muller and Liu, 1991), or in relation to

stand age and management regime (Woldendorp et al., 2002).

Only log biomass had signiﬁcant correlations with stand

attributes, likely a consequence of its lower variation relative to

CWD biomass and snag biomass. In the case of the Nothofagus-

dominated stand this relation was stronger with log biomass in

decay class III. This is not surprising since between one half and

two thirds of the plots in these stands correspond to ST and ST–

LT structures, which accumulated most of the plot/stand log

biomass, and with the highest concentration in decay class III

(Fig. 4). In consequence, in both stands we observed that

grouped plots dominated by ST (lower mean diameter or QMD)

had a higher abundance of log biomass in the most advanced

decay class (III), and that grouped plots dominated by medium

and large trees (MT and LT; higher QMD) had a lower

abundance of log biomass, with intermediate values for plots

with IR and ST–LT structures (Fig. 4), and an overall strong

relationship of log biomass and QMD in both stands. Plots with

structures dominated by ST likely belong to areas where LT

have fallen and the original logs are decaying. This coincides

with Spies et al. (1988) and Lambert et al. (1980), who found in

young forest stands a high proportion of CWD biomass in the

most advanced decay class, indicating the occurrence of a

disturbance that generated large quantities of CWD that

decayed as the forest stand regenerated.

Overall, QMD and structural type as classiﬁed by proportion

of trees of different sizes prove to be good predictors of log

biomass. The type of structure with the classiﬁcation used in

this paper has also proven useful to assess growth and

regeneration in Chilean old-growth forests (Donoso, 2005).

4.3. Comparisons with other temperate forests

There are few studies that have estimated CWD biomass in

temperate forests of the southern hemisphere. In Chile we know

of only the study by Carmona et al. (2002) in the evergreen

forest type in the Chiloe

´Island, who reported a CWD biomass

of 67 Mg ha

1

from 0.1-ha plots, a value intermediate between

the 89 Mg ha

1

that we reported for the Nothofagus-dominated

forest and the 59 Mg ha

1

reported for the Mixed-species forest

(Table 4). This is a reasonable comparison: canopy trees in old-

growth forest of south-central Chile (basically L. philippiana or

Podocarpaceae species in this case) have dominant heights

from 20 to 30 m, emergent N. dombeyi in the Andes have

heights that range from 40 to 50 m (Donoso et al., 1986; Parada

et al., 2003), and the dominant and/or emergent Eucryphia

cordifolia (Cav.) and Nothofagus nitida ((Phil.) Krasser) in

Chiloe

´usually reach 30–40 m in height (Donoso et al., 1985).

Since all these stands have basal areas close to 100 m

1

and a similar climate (408S in the Andes and 428S in the Chiloe

Table 4

CWD in old-growth temperate forests of North America and the southern hemisphere

Forest type Logs (Mg ha

1

) Snags (Mg ha

1

) CWD (Mg ha

1

)

Mean Range Mean Range Mean Range

Conifers—North America

63 54–73 54 41–63 117 95–136

Broad-leaved deciduous—North America

25 16–38 11 – 36 27–49

Broad-leaved evergreen—New Zealand

96 78–119 94 53–176 191 130–296

Tall open Eucalyptus—Tasmania

447 270–615 53 25–70 500 292–683

Mixed broadleaved-conifer—Chile

Evergreen forest type

47 31–65 126 13–349 174 58–381

Coigu

¨e–Raulı

´–Tepa forest type

Nothofagus-dominated

64 – 25 – 89 –

Mixed-species

53 – 6 – 59 –

Spies et al. (1988).

Harmon et al. (1986).

Stewart and Burrows (1994).

Woldendorp et al. (2002).

Carmona et al. (2002).

This work.

There are no ranges because it is only one forest stand.

B.C. Schlegel, P.J. Donoso / Forest Ecology and Management 255 (2008) 1906–19141912

Island), it is reasonable to expect a greater living and dead

woody volume from the forests with the tallest trees that

correspond also to pioneer species.

Compared to old-growth forests in other temperate

regions, the biomass of logs estimated in our study falls

behind the range of values estimated for conifer forests in the

western coast of North America, broad-leaved forests in New

Zealand and tall open Eucalyptus forests of Tasmania, is

about twice that estimated for deciduous forests of eastern

North America, and similar with CWD estimated from large

plots in the Ancud forests in Chile (Tab l e 4). The amount of

CWD is primarily a result of forest type, forest productivity (a

result of climate, soil and physiography) and disturbance

(Woldendorp et al., 2002). Forests dominated by tall

Eucalyptus in Tasmania or tall conifers in the Paciﬁc

Northwest of the USA, and forests with pioneer emergent

trees (Nothofagus-dominated forest in this study or the

Nothofagus-dominated forests of New Zealand) have more

CWD than forests lacking these species. Regions with lower

site productivity and production, such as the eastern region of

the USA (Barnes et al., 1999), or the Mediterranean region of

New South Wales in Australia (Woldendorp et al., 2002),

attain lower CWD biomass.

Results in the present study also suggests that the

successional phase may be considered another variable that

affects CWD, since old-growth forests which retain emergent

early-successional or pioneer tree species have a greater living

and dead woody biomass than forests lacking this component.

Consistently, the Nothofagus-dominated stand with 40–50 m

tall emergent N. dombeyi trees in this study ranks ﬁrst in CWD

biomass, followed by the Chiloe

´(Ancud) stands dominated by

the 30–40 m tall N. nitida and E. cordifolia trees, and lastly by

the Mixed-species stand of this study, which lacks emergent

trees. This can also be observed in the high amounts of CWD

reported for the New Zealand forests stands, which were old but

essentially even-aged (Stewart et al., 1991), with emergent

Nothofagus fusca trees, some sort of transition forest where

biomass is the greatest throughout succession (sensu Borman

and Likens, 1979).

Acknowledgements

We thank Roberto Godoy and Sabine Mu

¨ller-Using for

commenting on and revising this manuscript. This work was

supported by the International Foundation for Science D-3497-

1 to Pablo Donoso and Project FONDECYT No. 1050313.

Bastienne Schlegel acknowledges a Ph.D. fellowship from

CONICYT.

References

Armesto, J.J., Casassa, I., Dollenz, O., 1992. Age structure and dynamics of

Patagonian beech forests in Torres del Paine National Park, Chile. Vegetatio

98, 13–22.

Armesto, J., Leo

´n, P., Arroyo, M.K., 1995. Los bosques templados del sur de

Chile y Argentina: una isla biogeogra

´ﬁca. In: Armesto, J., Villagra

´n, C.,

Arroyo, M.K. (Eds.), Ecologı

´a de los bosques nativos de Chile. Universi-

taria, Santiago, Chile, pp. 23–28.

Barnes, B.V., Zak, D.R., Denton, S.R., Spurr, S.H., 1999. Forest Ecology,

Fourth ed. John Wiley & Sons, New York.

Borman, F.H., Likens, G.E., 1979. Pattern and Process in a Forested Ecosystem.

Springer-Verlag, New York.

Burschel, P., Gallegos, C., Martinez, O., Moll, W., 1976. Composicio

´ny

dina

´mica de un bosque virgen mixto de raulı

´y coigu

¨e. Bosque 1, 55–74.

Carmona, M.R., Armesto, J.J., Aravena, J.C., Pe

´rez, C.A., 2002. Coarse woody

debris biomass in successional and primary temperate forests in Chiloe

Island, Chile. Forest Ecol. Manage. 164, 265–275.

Christie, D.A., Armesto, J.J., 2003. Regeneration microsites and tree species

coexistence in temperate rain forests of Chiloe

´Island, Chile. J. Ecol. 91,

776–784.

Clark, D.B., Clark, D.A., Brown, S., Oberbauer, S.F., Veldkamp, E., 2002.

Stocks and ﬂows of coarse woody debris across a tropical rain forest nutrient

and topography gradient. Forest Ecol. Manage. 164, 237–248.

Diaconis, P., Efron, B., 1983. Computer-intensive methods in statistics. Sci.

Am. May, 116–130.

Donoso, C., 1989. Antecedentes ba

´sicos para la silvicultura del tipo forestal

siempreverde. Bosque 10, 37–53.

Donoso, C., 1993. Bosques templados de Chile y Argentina. Variacio

´n,

estructura y dina

´mica. Ecologı

´a Forestal. Universitaria.

Donoso, C., Escobar, R., Urrutia, J., 1985. Estructura y estrategias regenerativas

de un bosque virgen de Ulmo (Eucryphia cordifolia Cav.)–Tepa (Laurelia

philippiana Phil.) Looser en Chiloe

´, Chile. Rev. Chil. Hist. Nat. 58, 171–

186.

Donoso, C., Deus, R., Cockbaine, J.C., Castillo, H., 1986. Variaciones estruc-

turales del tipo forestal Coihue Raulı

´Tepa. Bosque 7 (1), 17–35.

Donoso, P.J., 2005. Crown Index: a canopy balance indicator to assess growth

and regeneration in uneven-aged forest stands of the Coastal Range of Chile.

Forestry 78 (4), 337–351.

Donoso, P.J., Nyland, R.D., 2005. Seedling density according to structure,

dominance and understory cover in old-growth forest stands of the ever-

green forest type in the coastal range of Chile. Rev. Chil. Hist. Nat. 78, 51–

63.

Donoso, P.J., Lusk, C.H., 2007. Differential effects of emergent Nothofagus

dombeyi on growth and basal area of canopy species in an old-growth

temperate rainforest. J. Veg. Sci. 18, 675–684.

Fraver, S., Wagner, R.G., Day, M., 2002. Dynamics of coarse woody debris

following gap harvesting in the Acadian forest of Central Maine, USA. Can.

J. Forest Res. 32, 2094–2105.

Gayoso, J., 2001. Medicio

´n de la capacidad de captura de carbono en bosques

nativos y plantaciones de Chile. Taller Secuestro de Carbono, Me

´rida,

Venezuela.

Goebel, P.C., Hix, D.M., 1996. Development of mixed-oak forests in south-

eastern Ohio: a comparison of second-growth and old-growth forests. Forest

Ecol. Manage. 84, 1–21.

Harmon, M.E., Hua, C., 1991. Coarse woody debris dynamics in two old-

growth ecosystems. Bioscience 41, 604–610.

Harmon, M.E., Franklin, J.F., Swanson, F.J., Sollins, P., Gregory, S.V., Lattin,

J.D., Anderson, N.H., Cline, S.P., Umen, N.G., Sedell, J.R., Lienkaemper,

G.W., Cromack Jr., K., Cummins, K.W., 1986. Ecology of coarse woody

debris in temperate ecosystems. Adv. Ecol. Res. 15, 133–302.

Hunter, M.W., 1990. Wildlife, Forests and Forestry; Principles of Managing

Forests for Biological Diversity. Prentice-Hall, New York.

Lambert, R.C., Lang, G.E., Reiners, W.A., 1980. Loss of mass and chemical

change in decaying boles of a sub-alpine balsam ﬁr forest. Ecology 61,

1460–1473.

˜hmus, A., Lo

˜hmus, P., Remm, J., Vellak, K., 2005. Old-growth structural

elements in a strict reserve and commercial forest landscape in Estonia.

Forest Ecol. Manage. 216, 201–215.

Muller, R.N., Liu, Y., 1991. Coarse woody debris in an old-growth deciduous

forest on the Cumberland Plateau, southeastern Kentucky. Can. J. Forest

Res. 21, 1567–1572.

Parada, T., Jara, C., Lusk,C., 2003. Distribucio

´n de alturas ma

´ximas de especies

en rodales antiguos de selva Valdiviana, Parque Nacional Puyehue. Bosque

24 (2), 63–68.

Quinn, G.P., Keough, M.J., 2002. Experimental Design and Data Analysis for

Biologists. Cambridge University Press, Cambridge, United Kingdom.

B.C. Schlegel, P.J. Donoso / Forest Ecology and Management 255 (2008) 1906–1914 1913

SFFC (Socie

´te

´Forestie

`re de Franche-Comte

´), 2000. Typologie des pepleuments

feuillus irre

´guliers de Franche-Comte

´. Thise, France, 32 pp.

Spies, T.A., Franklin, J.F., Thomas, T.B., 1988. Coarse woody debris in

Douglas–Fir forests of Western Oregon and Washington. Ecology 69 (6),

1689–1702.

Stewart, G.H., Burrows, L.E., 1994. Coarse woody debris in old-growth

temperate beech (Nothofagus) forests of New Zealand. Can. J. Forest

Res. 24, 1989–1996.

Stewart, G.H., Rose, A.B., Veblen, T.T., 1991. Forest development in canopy

gaps in old-growth beech (Nothofagus) forests, New Zealand. J. Veg. Sci. 2,

679–690.

Stone, J.N., MacKinnon, A., Parminter, J.V., Lertzman, K.P., 1998. Coarse

woody debris decomposition documented over 65 years on southern

Vancouver Island. Can. J. Forest Res. 28, 788–793.

Takahashi, M., Sakai, Y., Ootomo, R., Shiozaki, M., 2000. Establishment of tree

seedlings and water-soluble nutrients in coarse woody debris in an old-

growth Picea-Abies forest in Hokkaido, northern Japan. Can. J. Forest Res.

30, 1148–1155.

Tosso, J., 1985. Suelos volca

´nicos de Chile. Instituto de Investigaciones

Agropecuarias, INIA, Santiago.

Tyrrel, L.E., Crow, T.R., 1994. Dynamics of dead wood in old-growth hemlock-

hardwood forests in northern Wisconsin and northern Michigan. Can. J.

Forest Res. 24, 1672–1683.

Veblen, T.T., 1985a. Forest development in tree-fall gaps in the temperate rain

forests of Chile. Natl. Geogr. Res. 1, 162–185.

Veblen, T.T., 1985b. Stand dynamics in Chilean Nothofagus forests. In: Picket,

S.T.A., White, P.S. (Eds.), The Ecology of Natural Disturbances and Patch

Dynamics. Academic, New York.

Veblen, T.T., 1989. Nothofagus regeneration in tree-fall gaps in northern

Patagonia. Can. J. Forest Res. 19, 365–371.

Veblen, T., Ashton, D.H., 1978. Catastrophic inﬂuences in the vegetation of the

Valdivian Andes. Vegetatio 36, 149–167.

Veblen, T.T., Alaback, P.B., 1996. A comparative review of forest dynamics

and disturbance in the temperate rainforests of North and South America.

In: Lawford, R.G., Alaback, P.B., Fuentes, E. (Eds.), High-latitude

Rainforests and Associated Ecosystems of the West Coast of the

Americas: Climate, Hydrology, Ecology, and Conservation. Springer,

New York.

Veblen, T.T., Schlegel, F.M., Escobar, B., 1980. Structure and dynamics of old-

growth Nothofagus forest in the Valdivian Andes, Chile. J. Ecol. 68, 1–31.

Veblen, T.T., Donoso, C., Schlegel, F.M., Escobar, R., 1981. Forest dynamics in

south central Chile. J. Biogeogr. 8, 211–257.

Veblen, T.T., Schlegel, F.M., Oltremari, J.V., 1983. Temperate broad-leaved

evergreen forests of South America. In: Ovington, J.D. (Ed.), Temperate

Broad-leaved Evergreen Forests. Elsevier Scientiﬁc Publications B.V.,

Amsterdam, The Netherlands, pp. 5–31.

Veblen, T.T., Kitzberger, T., Burns, B.R., Rebertus, A.J., 1996. Perturbaciones

ydina

´mica de regeneracio

´n en bosques andinos del sur de Chile y

Argentina. In: Armesto, J.J., Villagra

´n, C., Arroyo, M.K. (Eds.), Eco-

logı

´a de los bosques nativos de Chile. Universitaria, Santiago, Chile, pp.

169–197.

Veblen, T.T., Kitzberger, T., Villalba, R., 2004. Nuevos paradigmas en ecologı

´a

y su inﬂuencia sobre el conocimiento de la dina

´mica de los bosques del sur

de Argentita y Chile. In: Arturi, M.F., Frangi, J.L., Goya, J.F. (Eds.), E-

cologı

´a y Manejo de Bosques de Argentina. Editorial de la Universidad

Nacional de la Plata, pp. 1–48.

Woldendorp, G., Keenan, K.T., Ryan, M.F., 2002. Coarse woody debris in

Australian forest ecosystems. A report for the national greenhouse strategy.

Bureau of Rural Sciences.

Woldendorp, G., Keenan, R.J., Barry, S., Spencer, R.D., 2004. Analysis of

sampling methods for coarse woody debris. Forest Ecol. Manage. 198,

133–148.

Zar, J.H., 1999. Biostatistical Analysis, Fourth ed. Prentice Hall, Inc.,

New Jersey.

B.C. Schlegel, P.J. Donoso / Forest Ecology and Management 255 (2008) 1906–19141914

Carbon density and sequestration in the temperate forests of northern Patagonia, Argentina

Article

Full-text available

Apr 2024

Introduction Forests are a crucial part of the global carbon cycle and their proper management is of high relevance for mitigating climate change. There is an urgent need to compile for each region reference data on the carbon (C) stock density and C sequestration rate of its principal forest types to support evidence-based conservation and management decisions in terms of climate change mitigation and adaptation. In the Andean Mountains of northern Patagonia, extensive areas of temperate forest have developed after massive anthropogenic fires since the beginning of the last century. Methods We used a plot design along belt transects to determine reference values of carbon storage and annual C sequestration in total live (above- and belowground biomass) and deadwood mass, as well as in the soil organic layer and mineral soil (to 20 cm depth) in different forest types dominated by Nothofagus spp. and Austrocedrus chilensis . Results Average total carbon stock densities and C sequestration rates range from a minimum of 187 Mg.ha ⁻¹ and 0.7 Mg.ha ⁻¹ .year ⁻¹ in pure and mixed N. antarctica shrublands through pure and mixed A. chilensis forests taller than 7 m and pure N. pumilio forests to a maximum in pure N. dombeyi forests with 339 Mg.ha ⁻¹ and 2.2 Mg.ha ⁻¹ .year ⁻¹ , respectively. Deadwood C represents between 20 and 33% of total wood mass C and is related to the amount of live biomass, especially for the coarse woody debris component. The topsoil contains between 33 and 57% of the total estimated ecosystem carbon in the tall forests and more than 65% in the shrublands, equaling C stocks of around 100–130 Mg.ha ⁻¹ in the different forest types. Conclusion We conclude that the northern Patagonian temperate forests actually store fairly high carbon stocks, which must be interpreted in relation to their natural post-fire development and relatively low management intensity. However, the current high stand densities of these forests may well affect their future carbon storage capacity in a warming climate, and they represent a growing threat of high-intensity fires with the risk of a further extension of burned areas in the future.

Climate-induced tree senescence leads to a transient increase in reproductive success of a large woodpecker species

Article

Full-text available

Sep 2021
SCI TOTAL ENVIRON

Climate change-induced mortality of trees is a concerning phenomenon for global forest ecosystems. The rapid decay and death of long-lived trees can significantly impact forest dynamics, with effects that transmit through ecological networks, becoming more evident in organisms occupying high trophic levels, such as large and specialized woodpecker species. However, understanding how populations of high trophic level species respond to climate change is still a challenge. In this study it was analyzed 32-year data of social groups of the Magellanic Woodpecker (Campephilus magellanicus) in North Patagonia, a region facing increasingly frequent droughts and increased temperatures. A positive trend in the size of woodpecker social groups as a response to climate-induced tree senescence was tested. A causal structural equation model examining climate- tree senescence- woodpecker relationships was used. Increasing nonlinear trends and positive interannual growth rates (>10%) for tree senescence and group size were found. Lowland forest sites had higher levels of tree senescence and more numerous social groups. The causal model supported the positive effect of mean temperature on tree senescence and the positive association of woodpeckers with tree senescence. These results provide evidence of a climate-induced increase in tree senescence that causes an increase in the size of woodpecker social groups. It is suggested that accelerated decay and mortality of trees in the northern Patagonian forests will decrease the stocks of deadwood in the long term, threatening the persistence of this large woodpecker species.

Growth decline and wood anatomical traits in Nothofagus dombeyi populations along a latitudinal gradient in the Andes, Chile

Article

Full-text available

Sep 2024
TREES-STRUCT FUNCT

There is evidence of recent declines in tree growth in the temperate forests of South America, due to the ongoing climate change. This study assessed growth-climate relationships and the xylem hydraulic architecture of coihue (Nothofagus dombeyi (Mirb.) Oerst) trees exposed to the warmer and drier conditions of recent decades. We selected four coihue populations along a latitudinal gradient in the Andes, Chile, corresponding to a wide range of variation in growing season precipitation (northern dry to southern wet sites). Tree-ring width was measured in 24–32 adult trees per site during the last 60 years. We measured wood anatomical traits in a subsample of four trees per site during the last 25 years. All data were correlated with climatic variables. During the studied period, SPEI-6 passed from positive to negative in all sites. Basal area increment decreased by 1.7 mm² year⁻¹ over the period 1960–2020. Tree-ring width had a positive correlation with precipitation at the drier sites and a negative correlation with maximum temperature at the wetter populations. We estimated a density of 1.78 × 10–4 and 1.2 × 10–4 vessels µm⁻² in the xylem of dry and wetter sites, respectively. Vessel density had a negative correlation with precipitation at the driest site and a positive correlation with maximum temperature at wetter sites. The hydraulic diameter was smaller under drier conditions, reaching 68–75 µm in the driest and wettest sites, respectively. Among the traits measured, vessel density was the most sensitive to climate. Drier and warmer conditions were associated with an increased number of smaller sized vessels, especially at the northern populations. Compared with the southern populations of our gradient, the northern populations growing at the drier sites are more sensitive to the ongoing changes in climate, and potentially more vulnerable to the even drier conditions projected for the future.

Do Managed Hill Sal (Shorea robusta) Community Forests of Nepal Sequester and Conserve More Carbon than Unmanaged Ones?

Article

Full-text available

Mar 2023

Nepalese community forests are globally recognized for sustainable forest management and improving the livelihoods of forest-dependent communities, but their contribution to carbon sequestration in trees and soil is rarely studied. This study was performed to understand the effect of management practices on carbon stock of two community forests (CFs) - Taldanda (managed) and Dangdunge (unmanaged) - dominated by Sal (Shorea robusta) in the mid-hills of Nepal. Twenty-one concentric sample plots, each of 250 m2, were laid out in each forest to estimate different carbon pools and a stratified random sampling intensity of 0.5% used to collect data. Results showed significant (p<0.05) differences in above and below-ground biomass and carbon sequestration potential between the two CFs. The managed and unmanaged forests had total carbon stock of 269.3±27.4 and 150.0±22.7 ton/ha, respectively, demonstrating 1.79 times higher carbon stock in the former than the latter. The managed forest had significantly (p<0.05) greater mean soil organic carbon (SOC) stock than the unmanaged forest. The SOC was highest in the upper soil layer (0-10 cm), with a steady decrease as the soil depth increased. All other measured carbon pools values were higher in managed compared to unmanaged forest. The difference in carbon stock was due to the manipulation of different forest management activities, including thinning, timber extraction, fire control, grazing, and fuel wood/fodder extraction. The study suggests that the implementation of proper forest management would be necessary for enhancing carbon stock in forest trees and soils.

Carbon stocks across different environments, disturbance regimes, and stand age in Fitzroya cupressoides forests, the longest-lived species of the southern hemisphere

Article

Full-text available

Sep 2022

Forest disturbances influence Fitzroya cupressoides forest structure and carbon stocks at multiple spatial and temporal scales. Natural disturbances such as landslides and volcanism affect and give rise to the mostly pristine Fitzroya stands present in the Andean cordillera. On the other hand, mostly human-caused fires and logging have been the main processes shaping the structure of Fitzroya stands in the Coastal range and of Fitzroya small remnants in the Central depression. The main goal of this study was to assess the carbon stocks and accumulation rates of Fitzroya forest stands according to their development stage under different disturbance regimes and environmental conditions given by the three physiographic units where the species grows (Coastal range, Central depression, and Andean range). The site selection included an age sequence of stands, known as a chronosequence approach. We identified Fitzroya post-disturbance stands in three different stages of development: young forest stage (mean stand age of the main cohort ≤ 200 years old), mature forest stage (200–800 years old), and old growth forest stage (800–1,500 years old). The following biomass components were considered: living standing trees, dead standing trees (snags), and logs from dead trees laying on the ground (coarse woody debris). Old-growth Fitzroya forests reached a mean total carbon stock (standing live trees, snags, and coarse woody debris) of 507, 279, and 331 Mg C ha ⁻¹ in the Andean and Coastal ranges, and Central depression, respectively. Fitzroya cupressoides contributes, in average, more than 80% to the total carbon stock in the Andean and Coastal ranges, and 63% in the Central depression. The remainder corresponds mainly to Nothofagus spp. The high carbon stocks in old-growth stands in the Andean range are explained by Fitzroya longevity, larger size, wood decay resistance, and the low recurrence of volcanic events. Carbon accumulation rates differ between the forests in the three physiographic units (Central depression>Andean range>Coastal range), mainly due to the different growth rates and environmental conditions present in each unit. In the context of climate change, conserving old-growth stands with large biomass and carbon stocks and restoring Fitzroya forests should be recognized as a key contribution toward national and global goals to mitigate global warming.

Canopy Gap Structure as an Indicator of Intact, Old-Growth Temperate Rainforests in the Valdivian Ecoregion

Article

Full-text available

Aug 2021

Forest degradation continues to increase globally, threatening biodiversity and the survival of species. In this context, identifying intact, old-growth forest stands is both urgent and vital to ensure their existence and multiple contributions to society. Despite the global ecological importance of the Valdivian temperate rainforests, they are threatened by forest degradation resulting from constant and intense human use in the region. Identification of remnant intact forests in this region is urgent to global forest protection efforts. In this paper, we analyzed whether forests-canopy alterations due to logging produce a distinctive canopy gap structure (e.g., a gap area and a fraction of canopy gaps in the forest) that can be used to remotely distinguish intact from altered forests. We tested this question by comparing the canopy gap structure of 12 old-growth temperate rainforests in south-central Chile (39–40° S), with different levels of canopy alterations due to logging. At each stand, we obtained aerial or satellite very high spatial-resolution images that were automatically segmented using the Mean-Shift segmentation algorithm. We validated the results obtained remotely with ground data on the canopy gap structure. We found that, in the variables, canopy gap fraction, gap area frequency distribution, and mean gap area could be measured remotely with a high level of accuracy. Intact forests have a distinct canopy gap structure in comparison to forests with canopy alterations due to logging. Our results provided a fast, low-cost, and reliable method to obtain canopy gap structure indicators for mapping and monitoring intact forests in the Valdivian ecoregion. The method provided valuable information for managers interested in maintaining and restoring old-growth forest structures in these southern-temperate rainforests.

Natural forests in New Zealand – a large terrestrial carbon pool in a national state of equilibrium

Article

Full-text available

Dec 2021

Background Natural forests cover approximately 29% of New Zealand’s landmass and represent a large terrestrial carbon pool. In 2002 New Zealand implemented its first representative plot-based natural forest inventory to assess carbon stocks and stock changes in these mostly undisturbed old-growth forests. Although previous studies have provided estimates of biomass or carbon stocks, these were either not fully representative or lacked data from important pools such as dead wood (coarse woody debris). The current analysis provides the most complete estimates of carbon stocks and stock changes in natural forests in New Zealand. Results We present estimates of per hectare carbon stocks and stock changes in live and dead organic matter pools excluding soil carbon based on the first two measurement cycles of the New Zealand Natural Forest Inventory carried out from 2002 to 2014. These show that New Zealand’s natural forests are in balance and are neither a carbon source nor a carbon sink. The average total carbon stock was 227.0 ± 14.4 tC·ha − 1 (95% C.I.) and did not change significantly in the 7.7 years between measurements with the net annual change estimated to be 0.03 ± 0.18 tC·ha − 1 ·yr − 1 . There was a wide variation in carbon stocks between forest groups. Regenerating forest had an averaged carbon stock of only 53.6 ± 9.4 tC·ha − 1 but had a significant sequestration rate of 0.63 ± 0.25 tC·ha − 1 ·yr − 1 , while tall forest had an average carbon stock of 252.4 ± 15.5 tC·ha − 1 , but its sequestration rate did not differ significantly from zero (− 0.06 ± 0.20 tC·ha − 1 ·yr − 1 ). The forest alliance with the largest average carbon stock in above and below ground live and dead organic matter pools was silver beech-red beech-kamahi forest carrying 360.5 ± 34.6 tC·ha − 1 . Dead wood and litter comprised 27% of the total carbon stock. Conclusions New Zealand’s Natural Forest Inventory provides estimates of carbon stocks including estimates for difficult to measure pools such as dead wood and roots. It also provides estimates of uncertainties including effects of model prediction error and sampling variation between plots. Importantly it shows that on a national level New Zealand’s natural forests are in balance. Nevertheless, this is a nationally important carbon pool that requires continuous monitoring to identify potential negative or positive changes.

Emergent properties of downed woody debris in canopy gaps: A response of the soil ecosystem to manipulation of forest structure

Article

Dec 2020
SOIL BIOL BIOCHEM

Natural forest disturbance events can influence soil biogeochemical processes in two ways-by creating downed woody debris (DWD; fallen tree boles or branches) and by creating canopy gaps that alter forest microclimate. DWD represents a substrate for microbial growth and a persistent store of carbon and nutrients, but microbial activity is also sensitive to temperature and moisture. We studied the potential interaction of DWD and canopy gaps on soil microbial processes, and wondered if microclimatic conditions resulting from the manipulation of forest structure would be enough to inhibit production, thereby altering a critical ecosystem process. Gaps and DWD (>10 cm diameter) were added to a maturing, even-aged, second-growth northern hardwood forest (the Flambeau Experiment; N Wisconsin, USA) to enhance structural complexity and promote key ecosystem processes typically associated with late-successional forests. We investigated the influence of DWD and gaps on soil microbial community composition, extracellular enzyme activity and soil characteristics. Soils were sampled near intermediately and highly decayed DWD and 2 m away from DWD (control) in gaps and closed canopy a decade after manipulation. DWD decomposition influenced the surrounding soil differentially depending on decay class and canopy condition. Mean C-and P-potential extracellular enzyme activities (BG, BX and AP) were enhanced near highly decayed DWD in gaps. The relative abundance of bacteria (actinomycete, anaerobic, gram-negative and gram-positive) remained constant in gaps but decreased from May to August in closed canopy. In gaps, soil total exchangeable cations increased by 34.6%, available phosphorus by 152% and fungal to bacterial ratios by 23.3% but temperatures decreased by 3.42% suggesting that canopy condition continues to affect soil properties and microbial processes a decade after gap creation. These results highlight the contribution of DWD to the forest floor and the influence of decaying wood characteristics on belowground ecosystems critical to future forest productivity. Retaining or adding heterogeneously distributed DWD of varying decay status may be essential to maintain ecosystem functions associated with nutrient cycling and microbial community dynamics in managed forests.

Restos ligninocelulósicos de gran tamaño en un bosque templado del sur de Chile

Article

Full-text available

Oct 2015

Resumen Los restos lignocelulósicos de gran tamaño (RLC), constituyen la necromasa en ambientes boscosos, y cumplen variadas funciones ecosistémicas. Se evaluó el volumen, necromasa, y estados de descomposición de RLC muertos, en un bosque templado de antiguo crecimiento (BTAC) dentro del Parque Nacional Puyehue, Centro-Sur de Chile. En 10 parcelas de 900 m2, se cuantificó los RLC (≥ 10 cm ϕ), cuya necromasa se clasificó empleando una escala de cinco categorías/estados de descomposición (1= menor degradación y 5= mayor degradación). Se encontró 632 m3 ha-1 de madera muerta (= 231,5 Mg ha-1 de necromasa), representados principalmente por Nothofagus betuloides (95,2%), siendo los troncos (52,7%) y ramas (35%), las estructuras vegetales más representativas (554,3 m3 ha-1 ≈ 203 Mg h-1). Estos resultados demuestran que los BTAC del sur de Chile son importantes reservas de litera leñosa gruesa, que contribuye a la biogeoquímica de estos complejos y remotos ecosistema. Abstract Coarse woody debris (CWD) are the necromass in wooded environments and comply with various ecosystems functions. Volume, necromass, and decay states of CWD dead in an old-growth temperate (OGTF) forest in Puyehue National Park, South-Central Chile were evaluated. In 10 plots of 900 m2 CWD was quantified (≥ 10 cm diameter), whose necromass classified using a scale of five categories/stages of decay, necromass (1 = lowest and 5 = highest degradation). We found 632 m3 ha-1 of deadwood (= 231,5 Mg ha-1 of necromass), mainly represented by Nothofagus betuloides (95,2%), being logs (52,7%) and branches (35%), the most representative plant structures (554,3 m3 ha-1 ≈ 203 Mg h-1). These results demonstrate that the OGTF of southern Chile are significant reserves of coarse woody debris, which contributes to the biogeochemistry of these complex and remote ecosystems. Restos lignocelulósicos de gran tamaño (necromasa) en un bosque templado de antiguo crecimiento del sur de Chile YACHANA Revista Científica, vol. 4, Edición Especial (noviembre de 2015) pp. 213-221.

A culture of conservation: How an ancient forest plantation turned into an old‐growth forest reserve – The story of the Wamulin forest

Article

Full-text available

Jul 2021

The global expansion of forest plantations at the expense of natural forests, especially old‐growth forests, raises concerns about habitat loss and a decline in ecosystem services. Natural regeneration of second‐growth forests with minimal human assistance has been suggested as a cost‐effective way to restore forests and increase forest ecosystem service potential. However, it is unclear whether natural regeneration will lead to the development of second‐growth forests similar to natural forests because most naturally regenerated second‐growth forests are still young. We present a case study of a very old second‐growth forest in southeastern China in which a forest plantation established approximately six centuries ago has now developed into an old forest with extraordinary high biodiversity levels, an immense carbon pool, and a rich culture. The forest was established in the 14th century because of a charitable contribution, became protected under the Chinese cultural norm of ‘unity between humans and the nature’, and was conserved because of the belief that the prosperity of people is closely linked to the prosperity of trees. The recent designation of the forest as a nature reserve further protects it from development despite competing land‐use demands related to recent economic growth. This case illustrates that, although human activity is the main cause for the disappearance and degradation of many forests, when human interests and cultural values align second‐growth restoration and subsequent forest conservation can lead to the successional development of old‐growth forests. Because this development takes multiple centuries, the protection of current second‐growth forests within conservation easements (e.g. nature reserves) and the reformation of culture values for the linkage of forests to human well‐being are key aspects of the continued conservation‐aided succession of second‐growth forests. A free Plain Language Summary can be found within the Supporting Information of this article.

Regeneration microsites and tree species coexistence in temperate rain forests of Chiloé Island, Chile

Article

Full-text available

Sep 2003
J ECOL

Summary 1 We studied the importance of fallen logs as recruitment sites for tree species, their role in species coexistence, and also the influence of canopy openness and litter depth on tree species establishment in mid-successional and old-growth temperate rain forests of Chiloé Island, southern Chile. 2 Old-growth (OG) stands showed significantly more fallen logs than mid-successional (MS) stands. Concomitantly, the proportion of seedlings and saplings established on logs was significantly greater in OG than MS stands. 3 Of 13 tree species found at our study sites, eight showed a significant bias towards establishment on logs, especially those in advanced stages of decomposition. 4 In some stands, all seedlings of Eucryphia cordifolia , Laureliopsis philippiana , Not- hofagus nitida , Tepualia stipularis and Weinmannia trichosperma occurred on decaying logs, whereas all Podocarpus nubigena seedlings were found on undisturbed soil sites. 5 Small-seeded species were more common on logs, whereas large-seeded trees occurred on soil. 6 On soil, litter depth negatively affected local abundance of log-dependent seedlings, suggesting that variation in litter accumulation influences species distributions across the forest floor mosaic. 7 The density of shade-intolerant seedlings was more enhanced by the presence of fallen logs under closed canopy than by the occurrence of canopy gaps over soil sites. 8 Seed size plays an important role in successful establishment of species across the mosaic of fallen logs and different litter depth on the forest floor. We suggest that this mosaic of microsites is an important factor for species coexistence.

Nuevos paradigmas en ecología y su influencia sobre el conocimiento de la dinámica de los bosques del sur de Argentina Chile.

Chapter

Full-text available

Oct 2004

Published in 2004

Los bosques templados del sur de Chile y Argentina: Una isla biogeográfica

Article

Jan 1996

Stand Dynamics in Chilean Nothofagus Forests

Chapter

Jan 2013

Thomas T Veblen

Perturbaciones y din??mica de regeneraci??n en bosques andinos del sur de Chile y Argentina

Article

Jun 1996

Pattern and process in a forested ecosystem. Springer-Verlag

Article

Jan 1979

Wildlife, Forests, and Forestry: Principles of Managing Forests for Biological Diversity

Article

Jan 2011

This book offers a broad geographic scope and conceptual focus that establishes general principles and guidelines for forest and wildlife management. Balanced in approach, it discusses both the macro and micro approaches to forest management and addresses how to implement and fund various plans.

Bosques Templados de Chile y Argentina, Variación, Estructura, y Dinámica

Article