ArticlePDF Available

Dendrochronology reveals planting dates of historic apple trees in the southwestern United States


Abstract and Figures

Historic apple orchards grow throughout the United States (5). Reconstructing histories of these orchards can offer valuable insights into local agricultural history and can be important documentation for historically significant landscapes. By applying standard dendrochronology techniques to historic apple orchards in central Arizona and southern Colorado, we successfully cross-dated ring growth between trees in the orchards, compared annual tree growth with local climate conditions, and determined minimum planting dates of the historic orchards. Our results indicate 1903 and late 1940s planting dates for two historic orchards in Arizona. An orchard near Ignacio, Colorado was planted prior to the late 1920s, though heart rot precluded finding the actual planting date. Tree ring dates from apple trees in the historic Pendley Orchard, Slide Rock State Park, Arizona generally compared closely with planting dates described in an oral history of the property, but showed some discrepancies with the older trees, most likely stemming from replanting events in the orchard. Climate response within historic orchards was less evident. One historic orchard showed moderate correlation with precipitation, but orchard growth appears more strongly controlled by local factors including irrigation and orchard maintenance. Our results indicate that if heart rot is absent from historic apple trees, dendrochronology is a useful tool for determining historic orchard planting dates.
Content may be subject to copyright.
Journal of the American Pomological Society 66(1): 9-15 2012
Dendrochronology reveals planting dates of historic
apple trees in the southwestern United States
Kanin J. routSon1 CoDy C. routSon2 anD PauL r. ShePParD3
1 University of Arizona, Arid Lands Resource Sciences, 1955 East Sixth St., PO Box 210184, Tucson, AZ 85719
Corresponding author: e-mail
2 University of Arizona, Department of Geosciences, Tucson, Arizona 85721
3 University of Arizona, Laboratory of Tree-Ring Research, Tucson, Arizona 85721
Historic apple orchards grow throughout the United States (5). Reconstructing histories of these orchards can
offer valuable insights into local agricultural history and can be important documentation for historically signicant
landscapes. By applying standard dendrochronology techniques to historic apple orchards in central Arizona and
southern Colorado, we successfully cross-dated ring growth between trees in the orchards, compared annual tree
growth with local climate conditions, and determined minimum planting dates of the historic orchards. Our results
indicate 1903 and late 1940s planting dates for two historic orchards in Arizona. An orchard near Ignacio, Colorado
was planted prior to the late 1920s, though heart rot precluded nding the actual planting date. Tree ring dates
from apple trees in the historic Pendley Orchard, Slide Rock State Park, Arizona generally compared closely with
planting dates described in an oral history of the property, but showed some discrepancies with the older trees, most
likely stemming from replanting events in the orchard. Climate response within historic orchards was less evident.
One historic orchard showed moderate correlation with precipitation, but orchard growth appears more strongly
controlled by local factors including irrigation and orchard maintenance. Our results indicate that if heart rot is
absent from historic apple trees, dendrochronology is a useful tool for determining historic orchard planting dates.
Throughout higher elevations of the
southwestern United States, remnant historic
orchards persist as vestiges of agricultural
endeavors in the region. For many of these
orchards, the planting dates, cultivars grown,
and the histories of the farmers who planted
them were never recorded. Historic trees
however, provide an extant, living record
of homestead agriculture through genetic
lineages and environmental influences
recorded in annual growth rings. Scientic
tools can be used to reconstruct these histories,
such as genetic analysis to reveal tree identities
(11, 12, 13, 26), tree and orchard architecture
as characteristic of different historic periods
(5), and dendrochronology to age historic
trees (22) and to reconstruct effects of
environmental variables such as drought
(17). Reconstruction of orchard histories can
offer valuable insights into early agriculture
not documented in the literature. Knowledge
of orchard planting dates can be important
in documenting and restoring orchards on
historically signicant properties. Orchards
and fruit trees were integral in U.S. settlement
history for food and beverages in subsistence
cropping systems and later as commercial
plantings of cash crops (5). With the rise of
modern orchard practices in the 20th Century,
apple cultivar diversity in the U.S. diminished
substantially (8, 25). Consequently, in addition
to historic value, historic orchards may
also contain genetic resources (26). Since
many later plantings contain commercial
cultivars, understanding orchard ages through
dendrochronology may be useful in evaluating
conservation priority of historic trees.
The xylem structure of apple [Malus x
sylvestris (L.) var. domestica (Borkh.) Mansf.]
is characterized in the Xylem Database (29)
as having distinct rings with diffuse porous
structure of solitary vessels separated by thin
to thick walled bers. Tree growth in the
spring predominates with the formation of
more early wood than late wood (17). Orchard
growing conditions can present challenges
to dendrochronology. Tree-ring widths may
reect only the irrigation schedule of the trees,
10 Journal of the american Pomological Society
precluding cross-dating (16). False rings in
the form of partial double rings have been
found (18). Fruit production can reduce ring
growth during “bearing” years or result in
double-ring formation depending on cultivar
(28). Heart rot commonly affects historic
apple trees (4) and may ultimately render them
unsuitable to dendrochronology. Orchards
on primitive farmsteads were often planted
with seedling trees, but grafted stock became
standard by the mid to late 19th Century (10).
Both seedling and grafted trees may be nursery
grown prior to planting in the orchard, and
it remains unclear how this will affect tree
growth or tree-ring dating except that orchard
establishment may post date the age of the
trees by a year or more depending on how old
the trees were when planting in the orchard.
Despite these challenges, historic orchards
have been aged and cross-dated (22).
Historic literature of apples in the Southwest
begins with early introductions of Old World
agricultural crops through Jesuit, Dominican,
and Franciscan missionary expeditions up
the Camino Real from Mexico City to Santa
Fe, New Mexico, by 1620 (6, 15). Later
introductions came in waves of settlement from
eastern and mid-western sources, beginning
in California and Utah before 1850 (7, 10).
Agricultural settlement closely followed the
opening of the region to trappers, miners, and
ranchers, and expanded with improvements in
transportation routes and irrigation technology.
Low annual precipitation confined early
orchard growing to ood terraces near streams
and springs that could be used for irrigation
(7). Pre-20th Century orchards were primarily
farmstead and small commercial plantings
for home use and to supply local mining and
logging boomtowns. The U.S. Department
of Agriculture actively participated in plant
introductions into the Southwest between 1887
and 1917 through agricultural experiment
stations enabled by the Hatch Act of 1887
[Mar. 2, 1887, ch. 314, § 1, 24 Stat. 440,7
U.S.C.361a et seq] (19). Mid-western mail-
order nurseries began advertising in the region
at least as early as the 1930s. The average
lifespan of apple trees is thought to be only 60-
100 years (24). Therefore, many of the living
historic orchards on the landscape likely date
to the later introductions of Anglo settlement
of the region.
We analyzed increment cores from apple
trees in historic orchards of unknown planting
dates to reconstruct planting times, and
cross-date their ring growth to determine the
extent of environmental variables recorded
in the trees. The Historic Pendley Orchards
at Slide Rock State Park, Arizona, with
oral history planting dates of 1932 in the
North Orchard, 1956 in the West Orchard,
and 1992 in the Experimental Orchard
were ideal for evaluating the application
of dendrochronology in assessing historic
orchards. Additional cores were taken from
abandoned farmstead orchards near Big Bug
Creek in the Prescott National Forest, AZ; at
Bottle Spring in the Tonto National Forest
outside of Young, AZ; and from the Crossre
Ranch outside of Ignacio, CO to determine
planting dates (Fig. 1).
Fig. 1. Sample collection sites: Pendley Orchard
at Slide Rock State Park, AZ (SLR), Big Bug Or-
chard in the Bradshaw Mountains, AZ (BBO), Bottle
Springs Orchard near Young, AZ (BSO), and Cross-
re Ranch Orchard, near Ignacio, CO (CRF).
Materials and Methods
Collection sites. Trees from the historic
Pendley Orchard at Slide Rock State Park
were cored in February 2010. Four trees were
cored from the 1932 North Orchard, from
trees 207 (‘Delicious’), 211 (‘Wolf River’),
228 (‘Delicious’), and 248 (‘Delicious’) as
maintained in the Slide Rock Orchard database
and labeled with aluminum tags at the base of
each tree. Five ‘Delicious’ trees were cored
from the 1952 West Orchard, from trees 264,
288, 292, 295, and 297. Three trees were
cored from the 1992 Experimental Orchard,
from trees 323 (‘Braeburn’), 326 (‘Fuji’) and
359 (‘Lura Red’). Tree cultivars, planting
dates, and numbers are documented in Tom
Pendley’s Oral History (23) and in the Slide
Rock State Park Orchard restoration final
report (21).
Twelve trees from the Big Bug Orchard
were cored in May 2010. Trees were labeled
with small aluminum tags by the author in
2007 during genetic sampling of the orchard
(26). Genetic analysis revealed ‘Westeld
Seek-no-Further’ as the dominant cultivar
in the orchard, precluding it from being a
seedling orchard.
The Bottle Springs Orchard was cored
in March 2010. These trees appear to be
largely seedling plantings based upon their
multi-trunk nature and observations of fruits
made by the authors in fall 2007. Trees were
assigned numerical identifiers and GPS
locations were recorded, but no tags were
nailed to trees. Three apple trees and ve
Ponderosa pine (Pinus ponderosa C. Lawson)
trees growing within the orchard were cored.
Four trees from the Crossre Orchard were
cored in May 2010. All trees were affected
with heart rot in this orchard and no complete
cores were extracted.
A single core was extracted from each
tree using a 3-thread, 5.15 mm increment
borer (Haglöf, Sweden), except in instances
where heart rot or internal branching or injury
prevented extraction of a usable core. In these
instances, two cores per tree were extracted.
Two cores were extracted from each of ve
Ponderosa pine trees in the Bottle Springs
Orchard. Cores were mechanically sanded
using 220-400 grit sandpapers. To determine
the age of trees and assign a calendar date to
individual growth rings, we used a technique
called cross-dating. Tree growth is inuenced
by factors at the individual tree scale (such
as pruning or differential watering), and
also at the site to regional scale by factors
such as climate. Cross-dating matches the
common growth patterns among trees at
each site and helps identify missing rings
and other issues such as false or double
rings discussed below. We used graphical
Fig. 2. Cross sections of apple wood revealing defuse-porous cell structure and annual ring growth. Cross
section A (above left) depicts an incomplete double ring; cross section B (above right) shows a partial ring
pinching out.
hiStoriC aPPLe treeS
12 Journal of the american Pomological Society
(27) and statistical (9, 14) methods to cross-
date the samples from each site. We then
measured the ring widths to generate raw
ring-width series from each tree. A 50-year
cubic smoothing spline (2) was applied to
the raw measurement series to standardize
and remove biological growth trends. The
standardized series were then compiled into
individual orchard chronologies (1). Tree
growth within orchards was compared to
climate records of precipitation and maximum
summer temperatures using correlation and
partial correlation analysis (20) with gridded
PRISM data (3).
Results and Discussion.
Cross-dating. Ring widths were cross-
dated among trees within all historic orchards
surveyed. Cross-dating, however was much
more difcult for young trees and trees in
orchards still being maintained than in the
older rings of abandoned orchards. Double
or false ring formation (two apparent growth
rings during the same year, Fig. 2A) can
make cross-dating difcult and appears to be
mostly associated with young, fast-growing
wood. Missing rings and partial rings can also
complicate cross-dating but were encountered
in only one of the Slide Rock cores. Missing
and partial rings occur when a tree is under
stressful conditions and cannot generate a
growth ring everywhere in the tree (Fig. 2B).
Raw ring width chronologies for all trees cored
in the four orchard sites are plotted in Fig. 3.
This gure reveals growth variance among
trees within each orchard.
Slide Rock planting dates. Tree ages were
determined for Slide Rock State Park (Table
I) and compared to orchard establishment
dates in the Tom Pendley Oral History Project
(23) and Park Service records for the 1992
Experimental Orchard. Several factors
can contribute to individual trees ages
not matching the exact date of orchard
establishment. Nursery-grown fruit trees are
typically sold at two years of age, but can be
three or four years old if too small or not sold
in the rst seasons. Trees can be added as later
Fig. 3. Raw ring-width series plotted for each tree cored in the Bottle Springs, Big Bug, Crossre, and Slide
Rock orchards.
replacements, or an orchard may be planted
over a period of several years. In addition, if
historic trees contained heart rot or the core
did not hit pith, the exact age of the tree is also
not precisely known. Inner-dates of the 1992
Experimental Orchard correspond well to this
planting date. Inner dates from older orchards
indicate 1930s and 1950s establishment dates,
but are not precisely aged to single planting
events. Specically, tree number 228 in the
North Orchard had an inner date of 1970 while
the orchard establishment from oral history
was nearly 40 years earlier. A later planting
to fill in open spaces could explain this
anomaly. In addition, tree number 297 in the
West Orchard showed an inner date of 1944,
predating the establishment of this orchard by
more than a decade. It is possible an orchard
existed at this site prior to the 1956 plantings
that correspond to the oral history and ages of
other trees in the orchard.
Unknown orchards. Individual orchard
chronologies were developed for the orchards
included in this study (Fig. 4). The year
1903 is the likely planting date for the Big
Bug Orchard. Tree piths all date to 1901 or
1902, but 1903 had a very narrow growth
ring. Being named cultivars, the trees were
grafted. Typically, nursery apple trees would
be grafted at one year of age, 50 – 80 mm off
the ground, then grown a year before being
sold. The very small ring in 1903 could have
been when the trees were rst transplanted
and establishing new roots in the rst season.
Below average precipitation for 1903 could
have also contributed to this narrow growth
ring. The Bottle Springs Orchard dates to
1946, and the Crossre Orchard dates to at
least the 1920s, though heart rot in the trees
prevented actual orchard establishment dates
from being determined.
Climate. Where there was a relationship
between the apple tree-ring chronologies
and climate, growth responded strongest to
annual precipitation ending in July of the
current growth year (Fig. 4). This is due to
spring-dominated growth responding to soil
moisture accumulated over previous months.
Tree-growth in apple orchards still being
maintained at Slide Rock show no signicant
correlation to climate, nor was there signicant
correlation in the now abandoned Big Bug
Orchard, possibly due to shallow groundwater
associated with Big Bug Creek nor with the
Crossre Orchard that receives ditch irrigation
during the summer months. Tree-growth
in the Bottle Springs Orchard, in contrast,
shows a moderate correlation to precipitation
Table 1. Planting dates and inner dates of apple trees in the Pendley Orchards at Slide Rock State Park.
Orchard Tree Variety Orchard Date Inner Date Pith
North 207 Delicious ~1932 1936 No pith
North 211 Wolf River ~1932 1948 No pith
North 228 Delicious ~1932 1970 Near pith (1-2yrs)
North 248 Delicious ~1932 1938 Near pith (2+ yrs)
West 264 Delicious ~1956 1954 Near pith (4+ yrs)
West 288 Delicious ~1956 1956 No pith
West 292 Delicious ~1956 1955 Near pith (~3+ yrs)
West 295 Delicious ~1956 1967 Near pith (~3+ yrs)
West 297 Delicious ~1956 1944 Pith? (0-1yr)
Experimental 323 Braeburn 1992 1988 Near pith (1-3yrs)
Experimental 326 Fuji 1992 1991 Near pith (~3yrs)
Experimental 359 Lura Red 1992 1993 Near pith (~2yrs)
hiStoriC aPPLe treeS
14 Journal of the american Pomological Society
(r = 0.43). Dry years were recorded by narrow
annual rings but average precipitation years
are more variable in ring growth. Ponderosa
pines growing within the Bottle Springs
Orchard pre-date the planting of the orchard
by over 10 years (the oldest Ponderosa pine
had an inner date of 1931), which is interesting
from a land-use perspective, where the apple
trees were planted between young pines. Ring
growth of the pines show a lower correlation
to precipitation than the apple trees (r = 0.30),
indicating different levels of sensitivity at this
site between the species.
This study confirms the utility of
dendrochronology in aging historic apple trees
and determining historic orchard establishment
dates, but also reveals challenges with
ascribing exact ages to orchards or individual
trees. Cross-dating between trees within the
orchards indicates the response of apple trees
to external environmental variables such as
climate or orchard management regimes and
can be useful in reconstructing environmental
histories associated with the historic orchards,
Fig. 4. Tree-ring chronologies developed for the four apple orchards. Local 12 month precipitation (3) end-
ing in July for each site is plotted with a dashed gray line behind the orchard chronology. The tree-ring and
precipitation series were normalized to z-scores (normalized departures from the mean), so that all the
series have a mean of zero and standard deviation of 1. This was done so tree-growth and precipitation are
in the same units and are comparable to each other.
though the ability to differentiate between
these external variables remains unclear.
Heart rot appears common in older apple trees
and precluded exact dating of the Crossre
Orchard. Results from this study indicate that
under favorable conditions, dendrochronolgy
methods can determine orchard establishment
dates, though heart rot may render these results
We sincerely thank Steve Pace, Frank
Vandevender, and the board of Slide Rock
State Park for permission to core the trees in
the park. Thanks to Rex Adams, Chris Baisan,
and other staff at the Laboratory of Tree-Ring
Research for their expertise and the use of
laboratory equipment.
1. Cook, E.R. 1985. A Time Series Analysis
Approach to Tree-Ring Standardization. Ph.D.
Thesis, University of Arizona, Tucson, Arizona.
2. Cook, E. R. and K. Peters. 1981. The smoothing
spline: A new approach to standardizing forest
interior tree-ring width series for dedroclimatic
studies. Tree-Ring Bulletin 41: 45-53.
3. Daly, C., W.P. Gibson, G.H. Taylor, G.L. Johnson
and P. Pasteris. 2002. A knowledge-based
approach to the statistical mapping of climate.
Climate Research 22: 99-113
4. Dodge, B. O. 1916. Fungi producing heart-rot of
apple trees. Mycologia 8(1): 5-15
5. Dolan, S. A. 2009. A Fruitful Legacy: A Historic
Context of Orchards in the United States, with
Technical Information for Registering Orchards in
the National Register of Historic Places. National
Park Service, Olmstead Center for Landscape
6. Dunmire, W.W. 2004. Gardens of New Spain:
How Mediterranean Plants and Foods Changed
America. University of Texas Press, Austin, Texas.
7. Fisher, D. V. and W. H. Upshall. 1976. History of
Fruit Growing and Handling in United States of
America and Canada, 1860-1972. Regatta City
Press Ltd, Kelowna, British Columbia.
8. Fowler, C. and P. Mooney. 1990. Shattering. Food,
Politics, and the Loss of Genetic Diversity. The
University of Arizona Press, Tucson, Arizona.
9. Grissino-Mayer, H. D. 2001. Evaluating cross-
dating accuracy: A manual and tutorial for the
computer program COFECHA. Tree-Ring
Research 57: 67-83.
10. Hedrick, U. P. 1950. A History of Horticulture
in America to 1860. Oxford University Press,
11. Hemmat, M., S. K. Brown and N. F. Weeden. 2003.
Mapping and evaluation of Malus × domestica
microsatellites in apple and pear. Journal of
American Society of Horticultural Science 128:
12. Hokanson, S. C., A. K. Szewc-McFadden, W. F.
Lamboy and J. R. McFerson. 1998. Microsatellite
(SSR) markers reveal genetic identities, genetic
diversity and relationships in Malus × domestica
Borkh. core subset collection. Theoretical Applied
Genetics 97: 671-683.
13. Hokanson, S. C., W. F. Lamboy, A. K.
Szewc-McFadden and J. R. McFerson. 2001.
Microsatellite (SSR) variation in a collection of
Malus (apple) species and hybrids. Euphytica 118:
14. Holmes, R. L. 1983. Computer-assisted quality
control in tree-ring dating and measurement. Tree-
Ring Bulletin 43: 69-78.
15. Jett, S. C. 1977. History of fruit tree raising among
the Navajo. Agricultural History 51(4): 681-701.
16. Kuniholm. P. I. 2001. Dendrochronology and other
applications of tree-ring studies in archeology. In:
The Handbook of Archaeological Sciences, D. R.
Brothwell and A. M. Pollard, Eds. John Wiley &
Sons, Ltd., London.
17. Lankes, C. and B. Neuwirth. 2009. Growth-
Rings in apple trees function as a source and
sink to balance impact of drought stress. Acta
Horticulturae 853: 151-156.
18. McMunn, R. L. 1939. Growth increment in
apple trees. Proc. of the American Society for
Horticultural Science 37: 106-109.
19. McOmie, A. M. 1918. Dry Farming in Arizona.
Agriculture Experiment Station Bulletin 84.
University of Arizona, College of Agriculture,
Tucson, Arizona.
20. Meko D. M., R. Touchan and K. J. Anchukaitis.
In review. Seascorr: a MATLAB program for
identifying the seasonal climate signal in an annual
tree-ring time series. Submitted to: Computers
and Geosciences.
21. Nabhan, G. P. and K. J. Routson. 2008. Slide Rock
State Park Orchard Restoration Final Report
for Project #640563. Center for Sustainable
Environments and Ecological Monitoring
& Assessment Program, Northern Arizona
University, Flagstaff, Arizona.
22. Neri, D., C. Urbinati, G. Savini and A. Sanchioni.
2005. Age Determination and Tree-ring Growth
Dynamics in Old Trees of Pyrus communis
‘Angelica’. Acta Horticulturae 671: 623-629.
23. Pendley, T. 2006. Oral history with Tom Pendley
May 15, 2006. Repository: Cline Library, Northern
Arizona University, Flagstaff, Arizona.
24. Pereira-Lorenzo, S., A. M. Ramos-Cabrer and
M. Fischer. 2009. Breeding Apple (Malus ×
domestica Borkh). In Mohan Jain, S. and P. M.
Priyadarshan, Eds. 2009. Breeding Plantation
Tree Crops: Temperate Species. Springer, New
25. Pollan, M. 2001. The Botany of Desire: A Plant’s-
Eye View of the World. Random House, New
York, New York.
26. Routson, K. J., A. A. Reilley, A. D. Henk and G.
M. Volk. 2009. Identication of historic apple trees
in the southwestern United States and implications
for conservation. HortScience 44(3): 589-594.
27. Stokes, M. A. and T. L. Smiley. 1968. An
Introduction to Tree-Ring Dating. University of
Chicago Press, Chicago, Illinois.
28. Tingley, M. A. 1936. Double growth rings in
red astrachan. Proc. of the American Society for
Horticultural Science 34: 61.
29. Xylem Database. Entry for Pyrus malus L.,
Rosaceae, Swiss Federal Research Institute, WSL, ,
accessed 05/05/11:
hiStoriC aPPLe treeS
... Tree-ring crossdating was recently used to determine stand demography of wild apple forests and the age of old orchards [19,20]. Yet to the best of our knowledge, the relationship between radial Apple has been studied extensively as a cultivated orchard tree, but its ecology in wild forests is less-well studied [13]. ...
... Tree-ring crossdating was recently used to determine stand demography of wild apple forests and the age of old orchards [19,20]. Yet to the best of our knowledge, the relationship between radial growth of apple trees and climate with dendrochronology has not been evaluated. ...
Full-text available
Wild populations of Malus sieversii [Ldb.] M. Roem are valued genetic and watershed resources in Inner Eurasia. These populations are located in a region that has experienced rapid and on-going climatic change over the past several decades. We assess relationships between climate variables and wild apple radial growth with dendroclimatological techniques to understand the potential of a changing climate to influence apple radial growth. Ring-width chronologies spanning 48 to 129 years were developed from 12 plots in the Trans-Ili Alatau and Jungar Alatau ranges of Tian Shan Mountains, southeastern Kazakhstan. Cluster analysis of the plot-level chronologies suggests different temporal patterns of growth variability over the last century in the two mountain ranges studied. Changes in the periodicity of annual ring-width variability occurred ca. 1970 at both mountain ranges, with decadal-scale variability supplanted by quasi-biennial variation. Seascorr correlation analysis of primary and secondary weather variables identified negative growth associations with spring precipitation and positive associations with cooler fall-winter temperatures, but the relative importance of these relationships varied spatially and temporally, with a shift in the relative importance of spring precipitation ca. 1970 at Trans-Ili Alatau. Altered apple tree radial growth patterns correspond to altered climatology in the Lake Balkhash Basin driven by unprecedented intensified Arctic Oscillations after the late 1970s.
... ships, discovery of former plantations, and restoration of nostalgic landscapes (Helama et al. 2017;Tucker et al. 2019). Dendrochronology can also be employed to determine the ecological aspects of a landscape during a historically significant period (Routson et al. 2012;Bleicher 2014;de Graauw and Hessl 2020). Dendroecological methods could be applied in a dendroarchaeological manner to provide a greater understanding of landscapes for conservation management. ...
Full-text available
The Cumberland Homesteads Historic District, located on the Cumberland Plateau in East Tennessee, is home to one of the first and largest Homesteads projects attempted during the New Deal era. Although the settlement did not succeed in its original objective, the history of the Cumberland Homesteads has become a valued foundation of the local community, which in turn strives to protect the legacy of the Cumberland Homesteads Tower. To preserve the integrity of the structure as well as the historical integrity of the landscape, the Cumberland Homesteads Tower Association sought to date and potentially remove trees that were not present during the period of significance (prior to 1938). The majority of the trees in close proximity to the Tower were identified as Eastern hemlock (Tsuga canadensis (L.) Carrire) and 15 trees total were sampled. Additionally, three post oak (Quercus stellata Wangenh.) trees located in a historic triangle across the highway from the Tower and targeted for removal were sampled. Samples were successfully dated, and ca. half of the hemlock were confirmed to have been planted after the construction of the Homesteads Tower. Additionally, post oaks analyzed near the Tower were dated back to the early 1800s, which motivated their protection in the midst of a road project threatening their survival.
... Cultivar identities, combined with dendrochronology, provide information regarding the time of orchard establishment by making use of information documenting when specific cultivars were available (Dolan 2009;Routson et al. 2009Routson et al. , 2012Volk and Henk 2016). ...
Full-text available
The National Historic Preservation Act of 1966 mandates that historic resources, including orchards, on federal lands be evaluated for potential significance. Evaluations include assessments and documentation of an orchard’s layout and location, as well as the architecture, ages, conditions, and cultivars of trees. These factors may reveal an orchard’s history and uniqueness and determine an orchard’s historic importance. Fruit tree cultivar identities are a key piece of this puzzle. They reveal information about an orchard’s use, origin, and uniqueness. In the past, historic preservationists relied on pomologists to identify cultivars based primarily on the phenotypic traits of the tree. DNA fingerprinting technologies, in combination with high-quality reference cultivar collections, have dramatically improved the accuracy of heritage cultivar identification. We demonstrate the utility of using DNA technologies for cultivar identifications on federal lands using examples from trees in orchards of Redwood National and State Parks and the Eldorado National Forest. A total of 87 historic apple trees from these locations were genotyped and cultivar names were determined for 35 trees, using a reference set of 1319 apple cultivars from the USDA National Plant Germplasm System, Washington State University, Seed Savers Exchange, and Temperate Orchard Conservancy. Some of the trees that were not identified may be cultivars that are not included in the reference sets and others may be unique trees derived from seeds. The information derived from genetic fingerprinting analyses will aid in the determination of the historic significance of orchards on public lands.
... However, a common problem is having to deal with partial tree-ring sequences due to inner rot destroying part of the core, so that the analysis of the tree-rings is hampered (cf. Groven et al., 2002;Routson et al., 2012). Samples with incomplete tree-ring sequences are often excluded, which can lead to less precision in the data, and sometimes inaccurate conclusions regarding, for example, forest age. ...
Full-text available
Trunk inner rot is a common phenomenon in some old-growth pine dominated forests, making it impossible to determine tree age by counting annual rings. We compared the efficiency of five methods to estimate the age of hollow pine trees (Pinus sylvestris L.). Our main aims were to select the best-performing method and to test whether the age of the tree or the proportion of rot influences the accuracy of estimation. We used full increment cores (reaching the pith or within 1 cm of it) from 100 trees (54–562 years old) collected in northern Sweden and simulated rotten centres of three different sizes in order to test the methods. The lowest error rates were obtained when less than a third of the sample was missing (down to 5.0 % error rate), and by using a method based on the growth pattern of a set of healthy trees. Using linear extrapolation of the mean radial growth led to large overestimates (up to three times the number of absent rings) with error rates up to 27.3 %. We also found that the performance of all methods was reduced in cores from older trees. Our main conclusion is that non-linear methods should be preferred for age estimation of hollow pines. We also argue that more precision in the age estimation could be gained already in the field by collecting multiple cores from rotten trees or by developing alternative coring methods.
Full-text available
We mapped DNA polymorphisms generated by 41 sets of Simple Sequence Repeat (SSR) primers, developed independently in four laboratories. All primer sets gave polymorphisms that could be located on our 'White Angel' x 'Rome Beauty' map for apple [Malus sylvestris (L.) Mill. Var. domestica (Borkh.) Mansf.]. The SSR primers were used to identify homologous linkage groups in 'Wijcik McIntosh', NY 75441-58, 'Golden Delicious', and 'Liberty' cultivars for which relatively complete linkage maps have been constructed from isozyme and Random Amplified Polymorphic DNA (RAPD) markers. In several instances, two or more SSRs were syntenic, and except for an apparent translocation involving linkage group (LG) 6, these linkages were conserved throughout the six maps. Twenty-four SSR primers were consistently polymorphic, and these are recommended as standard anchor markers for apple maps. Experiments on a pear (Pyrus communis L.) population indicated that many of the apple SSRs would be useful for mapping in pear. However some of the primers produced fragments in pear significantly different in size than those in apple.
Full-text available
The demand for spatial climate data in digital form has risen dramatically in recent years. In response to this need, a variety of statistical techniques have been used to facilitate the production of GIS-compatible climate maps. However, observational data are often too sparse and unrepresentative to directly support the creation of high-quality climate maps and data sets that truly represent the current state of knowledge, An effective approach is to use the wealth of expert knowledge on the spatial patterns of climate and their relationships with geographic features, termed 'geospatial climatology', to help enhance, control, and parameterize a statistical technique. Described here is a dynamic knowledge-based framework that allows for the effective accumulation, application, and refinement of climatic knowledge, as expressed in a statistical regression model known as PRISM (parameter-elevation regressions on independent slopes model). The ultimate goal is to develop an expert system capable of reproducing the process a knowledgeable climatologist would use to create high-quality climate maps, with the added benefits of consistency and repeatability. However, knowledge must first be accumulated and evaluated through an ongoing process of model application; development of knowledge prototypes, parameters and parameter settings; testing; evaluation; and modification. This paper describes the current state of a knowledge-based framework for climate mapping and presents specific algorithms from PRISM to demonstrate how this framework is applied and refined to accommodate difficult climate mapping situations. A weighted climate-elevation regression function acknowledges the dominant influence of elevation on climate. Climate stations are assigned weights that account for other climatically important factors besides elevation. Aspect and topographic exposure, which affect climate at a variety of scales, from hill slope to windward and leeward sides of mountain ranges, are simulated by dividing the terrain into topographic facets. A coastal proximity measure is used to account for sharp climatic gradients near coastlines. A 2-layer model structure divides the atmosphere into a lower boundary layer and an upper free atmosphere layer, allowing the simulation of temperature inversions, as well as mid-slope precipitation maxima. The effectiveness of various terrain configurations at producing orographic precipitation enhancement is also estimated. Climate mapping examples are presented.
COFECHA is a computer program that assesses the quality of crossdating and measurement accuracy of tree-ring series. Written by Richard L. Holmes in 1982, the program has evolved into one of the most important and widely used in dendrochronology. It is important to note that COFECHA does not perform all the necessary steps in crossdating. Rather, the program is a tool that helps the dendrochronologist assess the quality of crossdating and measurement accuracy. The ultimate decision whether or not a tree-ring series is successfully crossdated must lie with the dendrochronologist and not with the software. Therefore, the program is most useful after initial crossdating is accomplished using visual or graphical techniques (such as skeleton plots), and the rings have been measured. The proper use of COFECHA adds a high degree of confidence that tree-ring samples have been crossdated correctly and measured accurately, ensuring that the environmental signal is maximized. In this paper, I describe the use of COFECHA through all necessary steps, and discuss the meaning of the initial questions posed at program start-up, the various options available in the main menu, the various sections of the output from COFECHA, and interpretation of the diagnostics of crossdating and measurement accuracy. I demonstrate methods used to help crossdate undated series, and offer tips on taking full advantage of the various options available in the program.
The authors begin by outlining the role of the dendrochronologists both in the field and in the laboratory. The basic principles of tree-ring dating are then explained in detail, followed by a guide to the collection of archaeological and modern specimens from the field. The final section deals with the laboratory techniques used: the preliminary processing and preparation of archaeological and modern specimens; the process of dating specimens; and finally the compilation of a master chronology.