Robert S. Seymour

University of Maine | UM · School of Forest Resources

The maintenance of the earth's biological diversity is widely seen as both necessary for ecosystem integrity and aesthetically desirable. This book focuses on how biodiversity can be maintained in forested ecosystems, particularly in those forests that are subject to timber harvesting. At the core of the book lies the concept that diversity should...

Red spruce (Picea rubens) and balsam fir (Abies balsamea) are so similar that “spruce-fir” is often used as if it were a single species. The early monographs of Zon (1914) and Murphy (1917) accurately characterize both species as occupying a similar ecological niche: late-successional, very tolerant of shade, shallow rooted, and widely adapted to a...

Eastern North America's spruce-fir forests have a unique ecological and human history which is reflected in their current vegetation, ownership patterns, and forest management practices. Furthermore, there are important differences within the region between the true boreal forest and the sub-boreal Acadian forest; this paper emphasizes the Acadian...

Stand density management is central to achieving diverse silvicultural objectives. Decision-support tools in this domain range from expert opinion to sophisticated computer models that vary by forest type, region, and organization. The graphical frameworks represented by density management diagrams (DMDs) and stocking guides (SGs), collectively cal...

Natural disturbance-based silvicultural systems are forestry approaches that emulate ecological patterns and processes and are assumed to accommodate native bird assemblages better than conventional alternatives. The Acadian Forest Ecosystem Research Program (AFERP) represents the longest-running experimental application of expanding gap approaches...

The term "triad" in forestry refers to a landscape management regime composed of three parts: (1) intensive plantation management, (2) ecological forest reserves, and (3) a matrix of forests managed for multiple uses following the principals of ecological forestry. In this paper we review the sociohistorical and academic context for triad forest ma...

Reviews criteria for retaining residual trees in a partial harvest and when trees can be considered "mature."

Reviews Seymour's experience with the Husqvarna backpack chainsaw for understory beech control and precommercial thinning.

Reviews the use of historical land and census records to discover how your land was managed in the 1800s.

Reviews a Maine Woodland Owners field day on Seymour's Orcutt Mountain Tree Farm in Bucksport, Maine, on the topic of managing red oak in Maine.

Exploitation of natural forests forms expanding frontiers. Simultaneously, protected area frontiers aim at maintaining functional habitat networks. To assess net effects of these frontiers, we examined 16 case study areas on five continents. We (1) mapped protected area instruments, (2) assessed their effectiveness, (3) mapped policy implementation...

Disturbances play a fundamental role in shaping forest communities. It is therefore important to accurately quantify their frequency and magnitude in forest ecosystems. Tree-ring series are commonly used for relatively accurate detection of past disturbances. Currently, several dendroecological techniques exist that enable the detection of disturba...

Reviews a field day with Tom Allen, former Maine Congressman, on his family farm and woodlot in Sebago, Maine.

Reviews SocioSilv LLC's irregular shelterwood approach to managing Wicopy Woods, Maine's 2020 outstanding tree farm.

Reviews the practice of peeling and compares it to girdling.

Reviews recent FIA data on white pine saplings in Maine and discusses its silvicultural implications

Importance of looking at entire landscapes rather than individual stands when analyzing strategies to store more carbon in the forest

Principles of how forest sequester carbon, with examples from Seymour's white pine research

Importance and methods of forest sampling for woodlot owners

Techniques for monitoring diameter growth of trees

Reviews a tour of Mills' tree farm in Holden, Maine

Reviews new silviculture guide for eastern white pine published by NH Extension.

Reviews importance of correct silviculture terminology when describing treatments involving harvesting.

Reviews tool and techniques for silvicultural pruning in Maine

Explains pruning and why it is done in silviculture

Describes hardwood stand and how to minimize it in trees.

Reviews crown recession and how to manage it silviculturally.

Reviews natural regeneration ecology for Acadian tree species.

Reviews soil catenas in Maine, with their silvicultural importance.

Defines silvics and explains various silvical properties of trees.

This manual provides basic information for identifying and evaluating important health problems of eastern white pine in New England. The health problems include: • White pine weevil • White pine blister rust • Caliciopsis canker • White pine bast scale • White pine needle damage • Red rot or Red-ring rot In addition to providing descriptions of sy...

This study investigated the growth response of mature, isolated reserve trees (n = 528) in two multiaged silvicultural systems in the Acadian Forest Ecosystem Research Project (AFERP). Absolute and percent increases in basal area increment (BAI; cm²·year⁻¹) were assessed for the five predominant reserve tree species in AFERP: Acer rubrum L., Picea...

Eddy covariance methodologies have greatly improved our understanding of the forest carbon cycle, including controls over year-to-year variability in productivity (measured as net ecosystem productivity, NEP, where NEP is the difference between the mass of carbon fixed by photosynthesis and that lost by ecosystem respiration). However, establishing...

Update to the 2013 version which is now a bit outdated. Deleted non-database instructions and added many useful techniques for dealing with errors and management actions.

Understanding forest structural changes resulting from postdisturbance management practices such as salvage logging is critical for predicting forest recovery and developing appropriate management strategies. In 2013, a tornado and subsequent salvage operations in northern Maine, USA, created three conditions (i.e., treatments) with contrasting for...

In 1950, the US Forest Service initiated a cutting practice level (CPL) study on the Penobscot Experimental Forest in Maine on the basis of findings of a national appraisal of forestland management. Silvicultural treatments, including the selection system with 5- and 15-year cutting cycles, fixed diameter-limit cutting, and variants of commercial c...

Developing strategies for reducing atmospheric CO2 is one of the foremost challenges facing natural resource professionals today. The goal of this study was to evaluate total ecosystem and harvested wood product carbon (C) stocks among alternative forest management treatments (selection cutting, shelterwood cutting, commercial clearcutting, and no...

Maintenance of late-successional structures to enhance biodiversity and sequester carbon has been a major focus of forest research over the past two decades. Several long-term, disturbance-based silvicultural trials have been installed to try to balance the maintenance of complex forest conditions yet allow for economical extraction of timber. One...

Understanding the patterns of past disturbance allows further insight into the complex composition, structure, and function of current and future forests, which is increasingly important in a world where disturbance characteristics are changing. Our objectives were to define disturbance causes, rates (percent disturbance per decade), magnitudes and...

Understanding the response of tree regeneration following commercial thinning treatments can improve planning in managed forests dependent on natural regeneration. We used long-term commercial thinning experiments in eastern spruce–fir stands of Maine, USA, to test two hypotheses: (1) commercial thinning increases the density of tree regeneration a...

In: Kenefic, Laura S.; Brissette, John C., compilers. 2014. Penobscot Experimental Forest: 60 years of research and demonstration in Maine, 1950-2010. Gen. Tech. Rep. NRS-P-123. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station. 185 p.

Regenerating clearcuts dating from the spruce budworm outbreak of the 1980s are beginning to reach merchantable size throughout northern Maine and would benefit from commercial thinning, but there is no consensus among foresters and the logging industry about how such stands can be efficiently thinned. This study investigated silviculturally effect...

A general form for expressing gross volume increment in terms of stand density is derived and tested with data from spacing trials in red alder (Alnus rubra Bong.), eastern white pine (Pinus strobus L.), longleaf pine (Pinus palustris Mill.), and loblolly pine (Pinus taeda L.). The equation relates the stand sum of individual-tree volume increment...

Background/Question/Methods Gap-based silvicultural systems may offer an important approach for foresters and other resource managers who wish to adopt regeneration methods mimicking natural forest disturbance patterns and processes, particularly within systems in which disturbance dynamics are characterized by low intensity and long return interv...

We tested the hypothesis that changes in leaf area index (LAI m 2 m −2 ) and mean stand diameter following thinning are due to thinning type and residual density. The ratios of pre- to postthinning diameter and LAI were used to assess structural changes between replicated crown, dominant, and low thinning treatments to 33% and 50% residual density...

Taper models to predict upper stem diameters, as well as total tree volume, are presented for 11 major conifer species in the Acadian Forest Region of North America. The Kozak (2004. My last words on taper equations. For. Chron. 80:507‐514) Model 02 taper equation was used as the base model form. A nonlinear mixed-effects modeling approach was used...

Canopy leaf area index (LAI) is important for predicting stand growth response to silviculture, but it is difficult to quantify because of high variability, time constraints, and limitations of nondestructive techniques. We used an uninterrupted 17-year record of litterfall in a 60-year-old Pinus strobus L. plantation in central Maine to quantify L...

Throughout the northeastern United States, thinning is a common management practice in stands of eastern white pine (Pinus strobus L), but foresters lack clear information as to whether conventional B-line or low-density thinning will best achieve their growth and financial objectives. Conventional management consists primarily of light crown thinn...

Disturbance-based silvicultural systems generally seek to promote complex stand structures that are consistent with temporal and spatial patterns of natural disturbance while allowing for the sustainable harvest of timber. Gap-based harvesting systems are commonly used within this framework because they can be designed to approximate the frequencie...

We used stem analysis to quantify early height and diameter growth rates of 80 northern white-cedar trees (17.4-55.0 cm dbh) harvested in 2005 and 2006 in central and northern Maine. It took an average of 42 years (range, 9-86 years) for sampled trees to grow from stump height to sapling size, 96 years to grow to pole size (range, 28-171), 140 year...

Equations to predict branch and tree leaf area, foliar mass, and stemwood volume were developed from 25 destructively sampled northern white-cedar (Thuja occidentalis L.) trees, a species whose production ecology has not been studied. Resulting models were applied to a large sample of 296 cored trees from 60 sites stratified across a soil gradient...

Quantitative models of crown structure have been developed for several conifer species, but these studies have rarely simultaneously fit the models across multiple species. This study used extensive crown structure data for the five primary conifer species in Maine to test for species differences in maximum branch diameter profile, branch density,...

Leaf area index (LAI) strongly controls forest stand production. Silviculturists can easily manage this biologically important variable by quantifying its relationship to more directly manageable stand elements, such as density. Hypothesized patterns of LAI development over relative stand density (RD) in even-aged stands of balsam fir (Abies balsam...

Sustainability of the northern white-cedar (Thuja occidentalis L.) resource is a concern in many regions throughout its range because of regeneration failures, difficulty recruiting seedlings into sapling and pole classes, and harvesting levels that exceed growth. Management confusion has resulted from the scarcity of research on northern white-ced...

Vertical distribution of leaf area largely governs both tree structure and function. Models of this important tree attribute have been constructed for several commercially important conifers. However, a limited number of studies have compared alternative modeling techniques and inherent species differences. This study used several existing datasets...

Basal area growth of outwardly sound northern white-cedar (Thuja occidentalis L.) was compared with that of balsam fir (Abies balsamea [L.] Mill.) and red spruce (Picea rubens Sarg.) across site and light exposure class gradients on 60 sites throughout northern Maine. Once adjusted for sapwood area, northern white-cedar basal area growth was not st...

The influence of site index on growth efficiency was studied for 411 dominant and codominant Abies balsamea (L.) Mill. and Picea rubens Sarg. from 10 sites across Maine, USA. Young A. balsamea (n = 204) were from stands precommercially thinned 15-20 years ago and ranged in site index from 18.4 to 24.3, while the older P. rubens (n = 207) were from...

We examined the effect of management history on the availability of decayed downed wood and the use of downed wood as a regeneration substrate in mixed-species stands in the Acadian Forest of Maine. Regeneration of red spruce (Picea rubens Sarg.), eastern hemlock (Tsuga canadensis (L.) Carr.), balsam fir (Abies balsamea L. Mill), and red maple (Ace...

The northeast variant of the Forest Vegetation Simulator (FVS-NE) produces output that is of considerable use to forest managers in the northeastern United States. Designed to be relatively easy to use and requiring modest data inputs, FVS-NE is readily available at no cost and is well documented. However, as with all models, users need to apprecia...

Disturbance histories derived from old‐growth forest remnants in Europe and eastern North America have shaped many of our current theories of forest dynamics and succession. Yet the small size typical of these remnants suggests they might not capture the full range of variability that may emerge at larger scales. We investigated the frequency and s...

The effects of precommercial thinning (PCT) on stem dimensions, form, volume, and branch attributes of red spruce [Picea rubens Sarg.] and balsam fir [Abies balsamea (L.) Mill.] crop trees were assessed 25 years after treatment in an even-aged northern conifer stand. Treatments were a uniform 2.4 × 2.4-m spacing and a control (no PCT). The PCT trea...

Forests host a disproportionate share of the world's biodiversity. They are increasingly being seen as a refuge for genetic diversity, native species, natural structures, and ecological processes. Yet, intensive forestry threatens their value for biodiversity. The authors present concepts, approaches and case studies illustrating how biodiversity c...

Understory growth dynamics of northern conifer species were studied in four stands managed under multiaged silvicultural systems in eastern Maine. Height growth of Picea rubens Sarg., Abies balsamea (L.) Mill., and Tsuga canadensis (L.) Carr. saplings between 0.5 and 6.0 m in height was related to the proportion open sky (POS), using sapling height...

Growing white pines at low density after pruning appears to offer many advantages over more conventional silvicultural systems. This article describes how to design and implement a low-density thinning schedule using published relationships between crown architecture and stemwood growth; empirically, appropriate crown development can be maintained...

Using dendrochronological analyses, we reconstructed a 300 year history of eastern spruce budworm (Choristoneura fumiferana (Clem.)) outbreaks in northern interior Maine. By analyzing radial growth patterns from the budworm host, red spruce (Picea rubens Sarg.), and nonhost, northern white cedar (Thuja occidentalis L.), we identified five outbreaks...

This paper reviews experience and research findings from selected large-scale, long-term silvicultural experiments in four regions of the United States: the Northeast, the Lake States, the mid-South, and the Pacific Northwest. As early as the 1920s, when there was nationwide interest in multi-aged silviculture, researchers recognized that silvicult...

Though northern white-cedar is a common and economically important component of the Acadian Forest of Maine and adjacent Canada, there is little regional data about the growth and development of this species. Sixty sites in northern Maine were used to compare growth of cedar to that of red spruce and balsam fir along a range of site classes and lig...

We describe an alternative approach to the traditional stand-density management diagrams and stocking guides for determining optimum commercial thinning prescriptions. Predictions from a stand-growth simulator are incorporated into multiple nomograms that graphically display postthinning responses of various financial and biological response variab...

The foliage-sapwood area relationship (AL/AS) for balsam fir has been described in three separate studies with no less than four regression model forms. While there are clear differences in predicted AL values between the studies, it is not apparent if these differences are an artifact of the regression model form used or caused by regional differe...

To identify the highest priorities for silviculture research in Maine, the authors of this report quantified the absolute and relative influence of future silvicultural investments (tree planting, herbicide application, and PCT) and commercial thinning on projected harvest levels and future wood supplies in Maine. They also quantified the absolute...

The uniform stress hypothesis of stem formation was evaluated by comparing stem taper of Abies balsamea, Abies lasiocarpa, Picea rubens, Pinus contorta, Pinus elliottii, Pinus palustris, Pinus ponderosa, Pinus taeda, and Pseudotsuga menziesii to the taper expected if stems develop to uniformly distribute bending stress. The comparison was conducted...

Well-known patterns in the fundamental relationship between tree-level stemwood volume increment (VINC) and projected leaf area (PLA) are examined and quantified for Tsuga canadensis (L.) Carribre (eastern hemlock) and Picea rubens Sarg. (red spruce) growing in managed, mixed-species, multiaged stands in east-central Maine, U.S.A. Both species foll...

Many scientists and foresters have begun to embrace an ecological, natural disturbance paradigm for management, but lack specific guidance on how to design systems in ways that are in harmony with natural patterns. To provide such guidance, we conducted a comprehensive literature survey of northeastern disturbances, emphasizing papers that studied...

Dominant trees of shade tolerant species are often unsuitable for estimating site index because episodes of growth suppression can mask influences of site. A large-scale study in eastern Maine, based on 698 red spruce (Picea rubens) trees sampled with increment cores, and 92 trees sampled by stem analysis, addressed two objectives: (1) Can spruce t...

Tsuga canadensis (L.) Carr. (eastern hemlock) is a common species throughout the Acadian forest. Studies of leaf area and growth efficiency in this forest type have been limited by the lack of equations to predict leaf area of this species. We found that sapwood area was an effective leaf area surrogate in T. canadensis, though adding crown length...

A stand-density management diagram is presented for use in northeastern red spruce and balsam fir forests. The diagram was derived from an extensive archived data set collected during the 1970s from fully stocked stands throughout northern Maine and a more recent study of precommercially thinned stands. The negative exponential relationship between...