Dendroecological Analysis Research Articles

Spatio-temporal interpolation of climatic variables over large region of complex terrain using neural networks

Empirical models for seven climatic variables (monthly mean air temperature, monthly mean daily minimum and maximum air temperature, monthly mean relative humidity, monthly precipitation, monthly mean global solar irradiation and monthly potential evapotranspiration) were built using neural networks. Climatic data from 127 weather stations were used, comprising more than 30 000 cases for each variable. Independent estimators were elevation, latitude, longitude, month and time series of respective climatic variable observed at two weather stations (coastal and inland), which have long time-series of climatic variables (from mid last century). Goodness of fit by model was very high for all climatic variables ( R>0.98), except for monthly mean relative humidity and monthly precipitation, for which it was somewhat lower ( R=0.84 and R=0.80, respectively). Differences in residuals around model were insignificant between months, but significant between weather stations, both for all climatic variables. This was the reason for calculation of mean residuals for all stations, which were spatially interpolated by kriging and used as a model correction. Similarly interpolated standard deviation and standard error of residuals are estimators of the model precision and model error, respectively. Goodness of fit after the averaging of monthly values between years was very high for all climatic variables, which enables construction of spatial distributions of average climate (climatic atlas) for a given period. Presented interpolation models provide reliable, both spatial and temporal estimations of climatic variables, especially useful for dendroecological analysis.

The ancient use ofPinus sylvestris L. (Scots pine) inner bark by Sami people in northern Sweden, related to cultural and ecological factors

A multidisciplinary study of use by Sami people ofPinus sylvestris L. (Scots pine) inner bark was performed in northern Sweden. We combined linguistic, historical and archaeological records with ecological data collected from field studies to investigate important cultural and ecological factors associated with previous use of bark. Our data from bark peeled trees at 313 sites were used to describe patterns in space and time in the land-scape. Sites with bark peeled trees were mainly found in the central and northern part of Lapland (65°00′–68°14′N). Large numbers of barked trees were found in undisturbed forests in national parks and reserves but few were found in forests under commercial management. The dendroecological analysis revealed a continuous use of inner bark from A.D. 1450 to 1890. Large sheets of bark were taken from trees in the spring, prepared and stored as a staple food resource. Inner bark was eaten fresh, dried or roasted. Smaller bark peelings were used for the wrapping of sinews. The cessation of bark use in the 19th century was driven by several factors, but the availability of other products that could replace traditional use of bark was specifically important. The previous common and varied use of bark, the great age of Sami terminology and a possible association with archaeological remains of potential great age indicate that peeled bark was used long before the historic period. Our study also focused on the ongoing loss of culturally-modified trees in forests outside protected areas.

SPECIES AND STAND DYNAMICS IN THE MIXED WOODS OF QUEBEC'S SOUTHERN BOREAL FOREST

In order to test whether changes in forest composition observed while sam- pling portions of the landscape originating from different fires may be explained by stand- level processes, I reconstructed species and stand dynamics for mesic sites in the mixed- boreal forests of Quebec. The stands studied are located in the forest surrounding Lake Duparquet in northwestern Quebec and originated from eight successive fires representing a chronosequence of 230 yr. Tree composition and ecological characteristics were assessed in 313 quadrats distributed systematically within the burned areas; one representative stand per fire, presenting the average species composition for clay soils with a moderate moisture regime, was selected for detailed dendroecological analysis. All living and dead stems (> 1 cm dbh) were mapped and cut down in a 20 x 20 m quadrat. Cross sections collected at the root collar and at every meter were analyzed using standard dendrochronological techniques. The age of the stand before the last fire was estimated using snags and logs located in, or in the vicinity of, each quadrat. A PCA (principal-components analysis) ordination of all quadrats shows a gradual change with time since fire from stands dominated by hardwoods (aspen and paper birch), to mixed stands with an important white spruce component, to coniferous stands dominated by balsam fir and white cedar. Despite variations in the age and composition of the stands before the last fire, they generally follow a common pattern characterized by post-fire hardwood dominance. Age structures show successive waves of aspen, birch, and fir re- cruitment, corresponding respectively to the post-fire cohort, the gradual dismissal of the first aspen cohort, and spruce budworm outbreaks. Each of these waves corresponds to a decrease in hardwoods and an increase in the conifer component of the stand. Suppressed white spruce individuals, recruited primarily as part of the post-fire cohort, experienced growth releases following the dismissal of the first aspen cohorts. White cedar increased in abundance late in succession and tended to outcompete balsam fir in old coniferous stands severely affected by spruce budworm outbreaks. The observed multi-cohort process contrasts with the simple replacement of hardwoods by conifers as suggested by observations of differential growth rates. The patchy distribution of conifer regeneration together with the poorer ability of conifers to rapidly fill gaps may explain why hardwoods are successfully recruited. This gradual rate of change, occurring over several generations, results in the maintenance of an important hardwood component in most stands even in the absence of fire. After 230 yr, stands are still mainly composed of trees originating from punctuated events such as fire, the gradual dismissal of the first aspen cohort, or spruce budworm outbreaks. This contrasts with old-growth boreal forests dominated by spruces in which a quasi-equilibrium is maintained by small canopy distur- bances. The study confirms that changes in forest composition observed while sampling portions of the landscape originating from different fires may be explained by simple processes occurring at the stand level.

Dendroecological Analysis of a Mature Loblolly Pine-Mixed Hardwood Forest at the George Washington Birthplace National Monument, Eastern Virginia

ABRAMS, M. D., AND B. A. BLACK. (School of Forest Resources, Pennsylvania State University, University Park, PA 16802). Dendroecological analysis of a mature loblolly pine-mixed hardwood forest at the George Washington Birthplace National Monument, eastern Virginia. 127:139-148. 2000.-The composition, structure, and dendroecology of a mature pine-hardwood forest was studied at the George Washington Birthplace National Monument, eastern Virginia. Loblolly pine, sweetgum, holly, blackgum, and several oak species dominate the forest. Blackgum trees dominated recruitment from 1840 to 1900, based on current age structure. All other tree species are less than 100 years old. A compilation of major and moderate radial growth releases revealed multiple disturbance events in most decades from 1870 to 1990. A dramatic increase in the radial growth of blackgum occurred in the late 1880s, probably in response to selective logging of pine and hardwood timber species. This disturbance stimulated the recruitment of blackgum followed by loblolly pine and other hardwood species. A decline in blackgum recruitment occurred during the 20th century. The existing loblolly pine range in age from 64 to 105 years old, and this species stopped recruiting in 1935. The loblolly pine standardized (ARSTAN) chronology was positively correlated, and blackgum negatively correlated, with current and previous year temperatures. There were no correlations with Palmer drought severity index or precipitation. Seedlings and saplings of all species are scarce, with the exception of holly, a highly shade tolerant, understory tree species. Loblolly pine trees in the overstory may exhibit future declines due to their relatively short longevity, insect attack, and windthrow. Given current conditions, the future stand composition most certainly will contain less loblolly pine and more hardwoods, including sweetgum, blackgum, and holly.

Structure and stand development in three subalpine Norway spruce (Picea abies (L.) Karst.) stands in Paneveggio (Trento, Italy)

Summary 1. Three permanent plots (100×0 m) were established in the subalpine Norway spruce (Picea abies (L.) Karst.) forest of Paneveggio in the spring of 1993, to begin a long‐term forest ecosystem research project. The main purpose of these plots was to provide information about subalpine Norway spruce stand dynamics and to provide suggestions for close‐to‐nature silviculture. 2. The three stands were selected to represent the most common forest structures in the Paneveggio forest. The first stand is close to forestry roads, has a relatively regular and continuous canopy, and thinning and cutting operations only ended in the 1980s; the second stand is far from forest roads and has developed without anthropogenic influence for several decades; the third one is located at the present upper limit of the pure spruce forest and, apparently, was heavily used in the past as a pasture. 3. The first step in the investigation was to describe the structure and to study the history of the three stands using both written evidence from manage‐ ment plans and biological archives from tree rings. 4. The stands in plots 1 and 2 began to establish after a disturbance that removed part of the previous stands according to dendroecological studies, which are partially supported by written evidence. The remaining parts of these stands were eliminated by two major disturbances that occurred during the following decades. Written records about the use of the forest lead us to assume that the initial disturbances that occurred in the two stands were logging activities as a part of a group shelterwood system. The stand in plot 2 has developed without significant human interference for about half a century as confirmed by the presence of many dead trees. The stand in plot 3 consists of old trees that were part of an open stand and a secondary population that established after cessation of grazing. 5. The study has confirmed that dendroecological techniques can be used to identify occurrence and intensity of previous disturbance in forests stands, although at Paneveggio it is difficult to distinguish between natural and anthropogenic disturbances in the tree ring record. The presence of human activity necessitates investigation of multiple lines of evidence. 6. Paneveggio's forest management plans were useful in the interpretation of the data obtained through dendroecological analysis, although events did not always correspond because data from the management plans (yearly thinning, felling, wind‐throw damage) never gave stand‐level details, but applied to areas of several hectares. Despite these limitations, the information included in the management plans is of crucial importance in studying stand history and only by using all these sources of information is it possible to delineate the most important features of the history and disturbance that affected the origin and subsequent growth of the forest stands.

Dendroecological Analysis of the Population Dynamics of an Old-Growth Forest on Cliff-Faces of the Niagara Escarpment, Canada

1 We examined temporal fluctuations in age structure and population dynamics in an ancient forest of Thuja occidentalis on cliff-faces of the Niagara Escarpment, Canada. Living stem density was 1003 stems ha-' and total numbers of dead stems and living trees on the cliff and in the talus were consistent along the length of the cliff-face, and similar to other old-growth forests. 2 The extreme longevity of T. occidentalis and the presence of persistent coarse woody debris provided a rare opportunity to reconstruct the palaeodemography of this forest, to determine whether the stable uneven-aged structure is indicative of a forest population free of disturbance and existing in a steady-state condition. 3 The forest had maintained a stable uneven-aged structure or reverse-J age structure with no evidence of disturbance for the 12 reconstructed years between 1770 and the present. There had been a net population reduction since 1770, with mortality rates exceeding recruitment rates over the last 140 years. While recruitment rates had varied, there had been continuous recruitment and survival of seedlings over this time. 4 Synchronous radial growth releases occurred in over 20% of the dated trees during 11 years between 1450 and 1992. Synchronous radial growth suppression occurred during three other years. 5 Cliffs and other rock outcrop ecosystems may, as a class of habitat types, represent systems that are locally constant, even when their neighbouring communities experience large-scale disturbance.

Subalpine tree growth on serpentine soil: a dendroecological analysis

In this study dendrochronological methods are used to investigate tree growth of several coniferous species growing on serpentine outcrops in the subalpine region. Though stands are thriving on the same parent material, almost barren sites covered with Scots pine trees (Pinus sylvestris/ L.) contrast sharply with adjacent dense stands composed of mixed coniferous species. To find a reasonable explanation for this vegetation pattern and to evaluate the influence of serpentine soil on radial tree growth annual variability in ring-widths was analyzed and compared between both types of stands. Tree-ring analyses show that sparse tree cover on steep slopes might be caused by environmental stress factors especially unfavourable physical soil properties such as instability and dryness. Several abrupt growth reductions followed by slow release in ring-widths indicate repeated mechanical injury to the root system due to soil erosion. On the other hand the aggravating impact of anthropogenic disturbances (tree felling) on this ecologically fragile serpentine area could be determined and dated. There was no evidence that radial tree growth of coniferous species at this site could be limited by toxic heavy metals in the soil.

Composition, Structure, and Disturbance History of Crabtree Woods: An Old- Growth Forest of Western Maryland

MCCARTHY, B. C. AND D. R. BAILEY. (Department of Environmental & Plant Biology, Ohio University, Athens, OH 45701-2979). Composition, structure, and disturbance history of Crabtree Woods: an old-growth forest of western Maryland. Bull. Torrey Bot. Club 123: 350-365. 1996.-Crabtree Woods is an old stand of mixed Appalachian hardwoods which has been identified as one of the finest examples of this vegetation type in Maryland. Because few botanical studies have been conducted on the Allegheny Plateau of Maryland and because the old-growth nature of this stand is unique in its present landscape, we undertook this study to describe the composition, structure, and disturbance history of the stand. A one hectare permanent plot was established in which all trees, saplings, snags, and logs were quantified. Woody seedlings and herbs were subsampled from 25 quadrats to describe the understory. Increment cores were obtained from all Quercus rubra trees within the plot and used for dendroecological analysis. The stand shows many structural and compositional features characteristic of old-growth forest. The overstory was dominated by Acer saccharum, Q. rubra, and Tilia americana. The stand exhibited a reverse-J diameter distribution typical of old forests and a number of trees were observed to have a diameter >100 cm DBH. Acer saccharum and Hamamelis virginiana were the prominent understory constituents. Quercus rubra was essentially absent from seedling and sapling size classes and does not appear to be regenerating. Logs and snags were abundant and occurred in a variety of decay states and diameter classes. Thirty-nine species of herbs were discovered, with Dicentra canadensis, Urtica dioica, and Impatiens pallida being the most abundant. Stem increment analysis shows multiple periods of recruitment likely associated with gap dynamics. However, certain synchronous releases suggest possible light anthropogenic disturbance (e.g., selective cutting or chestnut salvage).

Errata: Dendroecological analysis of Successional Dynamics for a presettlement-origin white-pine-oak forest in the southern Appalachians, USA

Errata: Dendroecological analysis of Successional Dynamics for a presettlement-origin white-pine-oak forest in the southern Appalachians, USA

The natural revegetation of a harvested peatland in southern Québec: A spatial and dendroecological analysis

In North America peat has been harvested for horticultural use since the beginning of the 20th century. Many peatlands are now abandoned after decades of mining, and natural revegetation of peat oc...

Growth and Fire Response of Selected Epacridaceae of South-Western Australia

Recruiting populations of seeder (Astroloma xerophyllum (DC.) Sond. and Leucopogon conostephioides DC.) and resprouter (Leucopogon verticillatus R.Br. and Conostephium pendulum. Benth.) epacrids were examined over an 8 year period, using time of fire, shoot morphology and root xylem ring number to age plants. The seeders commenced flowering earlier, achieved three-fold higher shoot:root ratios but accumulated much smaller root starch reserves than the resprouters. The resprouting potential of L. verticillatus was 'bud initiation-limited', since progressive shoot removal exhausted the bud-producing potential but did not fully deplete the starch reserves of the root stock. Apparent conversion efficiency of starch to new shoot biomass was 88%. The corresponding response in C. pendulum was 'energy reserve-limited', with shoot removal eliminating root starch but leaving many unexpanded buds. Dendroecological analyses of root xylem growth rings were undertaken on 15 year-old plants of C. pendulum recruiting from seed in unburnt and adjacent periodically burnt habitats. Growth ring extension of burnt plants resumed after each fire at rates faster than their unburnt counterparts, suggesting that improved access by resprouting shoots to light, water and nutrients compensated for destruction of the previous shoot system.

Growth response of subalpine fir (Abies lasiocarpa) to climate in the Olympic Mountains, Washington, USA

AbstractGrowth response of subalpine fir (Abies lasiocarpa) to climate was studied across its local geographical and elevation range in the Olympic Mountains, Washington. A dendroecological analysis of subalpine fir across a range of elevations (1350‐1850 m) and annual precipitation (125‐350 cm y−1), was used to compare environmental factors affecting growth. Climate‐growth relationships were explored using Pearson product‐moment correlation coefficients; partial correlation analysis was used to assess relationships among site chronologies and climatic variables. Radial growth is negatively correlated with winter precipitation at high elevation and wet sites, but not at low and middle elevation dry sites. Growth is positively correlated with current growing season temperature at all sites; however, growth is negatively correlated with previous year August temperature, indicating that climate affects growth in subsequent years. Positive correlations between growth and summer precipitation during the growing season at low and middle elevation dry sites suggest that soil moisture is partially limiting to growth on these sites. If the climate of the Pacific Northwest becomes warmer and drier, then subalpine fir growth may increase at high elevation and wet sites, but may decrease at lower elevation dry sites in the Olympic Mountains. However, the growth response of subalpine fir to potentially rapid climate change will not be uniform because subalpine fir grows over a wide range of topographic features, habitats, and local climates at different geographical scales. A comparison of growth response to current growing season temperature suggests that the temperature‐related growth response of subalpine fir is not adequately described by the parabolic curve used in JABOWA‐based models.

Dendroecological Analysis of Successional Dynamics for a Presettlement- Origin White-Pine-Mixed-Oak Forest in the Southern Appalachians, USA

1 Prior to European settlement, Quercus alba, Castanea dentata, Carya spp. and Pinus strobus dominated Ridge and Valley forests in southern West Virginia. Dendroecological techniques were used to study the disturbance history and successional dynamics of one of the few remaining valley-floor remnants of this primary forest type. 2 The uneven-aged forest is presently dominated by P. strobus, Acer rubrum, Q. alba, Q. rubra and Q. velutina. Quercus alba and P. strobus represented most of the oldest and largest trees in the forest, while Acer, Fagus and Tsuga were the youngest and smallest. Maximum age was 295 years for Q. alba and 231 years for P. strobus. 3 There was continuous recruitment of Q. alba trees from 1700 to 1900. The abundance of P. strobus increased between 1830 and 1900, with a peak in the 1870s associated with releases in radial growth. The subsequent peak recruitment of Q. rubra and Q. velutina from 1880 to 1900 is suggestive of possible facilitation of these species by P. strobus. Following the cessation of Pinus and Quercus recruitment in 1900, Acer, Fagus and Tsuga abundance increased, particularly A. rubrum. 4 Radial growth chronologies across all species and age classes exhibited a series of major or moderate releases at regular intervals (typically every 20-30 years). However, the asynchronous nature of these releases suggests that they were caused by a series of small-scale disturbances, such as fire and wind-throw, each of which had localized impacts within the stand. 5 We believe that Pinus and Quercus were maintained in this stand during the 18th and 19th centuries by periodic disturbance, in particular fire, which would have eliminated later successional species. The lack of Pinus and Quercus recruitment after 1900 and the subsequent increase in Acer, Fagus and Tsuga indicates the transitional nature of this forest in the absence of fire. 6 Coupling of tree-ring chronologies and species establishment dates greatly increased our understanding of the disturbance history and dynamics of this old-growth forest, and we believe this represents an important approach to the study of species lifehistory attributes and ecological history in general.

Postfire stand dynamics in a southern boreal forest (Québec): A dendroecological approach

Arboreal succession in the southern boreal forest of Québec was documented through a dendroecological analysis of a mid-successional stand originating from fire 75 years ago. The studied stand was located in the forest surrounding Lake Duparquet, south of Lake Abitibi in northwestern Québec. Tree composition and ecological characteristics were assessed in quadrats distributed systematically within the burnt area. One site was selected for a detailed dendroecological analysis as it was representative of the average composition found on moderately well-drained clay deposits. In a 20 m × 20 m quadrat, all living and dead tree stems (> 1 cm d.b.h.) were mapped and cut down. Cross sections collected at the root collar and at every metre were analyzed using standard dendrochronological techniques. While the prefire composition was characterized by an old (> 210 years) forest of Thuja occidentalis L. and Abies balsamea (L.) Mill., Populus tremuloides Michx and Betula papyrifera Marsh dominated the composition of the burnt area. These two species, originating most likely from suckering and sprouting, were recruited immediately after the fire while most of the Picea glauca (Moench) Voss and Abies regeneration was delayed for five years. Most Populus rapidly attained dominance while, with few exceptions, the other species were suppressed and occupied lower positions in the canopy. Differences in growth between Populus and Betula were accentuated by an important growth decrease in the mid-1950s, from which only Populus had fully recovered. Defoliation by the forest tent caterpillar caused hardwood growth decrease in the 1950s, as well as previous ones, while defoliation by the spruce budworm caused growth decreases and mortality in conifers around 1940 and from 1972 to 1987. Picea and Abies were regularly recruited since the fire and they formed an abundant understory cover. The recent recruitment of a few Thuja seedlings may be incidental or related to an increase in mosses with time since fire. Our results suggest that all species, except Thuja, can be abundant in the postfire cohort and that differences in diameter and height among species were explained by their respective growth and not by successive species invasion. This relatively regular stand development was, however, significatively influenced by episodes of insect defoliation. Mechanisms involved in subsequent stands development towards the mixed and coniferous compositions observed in older stands cannot be easily extrapolated from the present stand structure. Similar studies are therefore needed to explain these mechanisms in older stands.

The Effects of Repeated Prescribed Burning on Pinus ponderosa Growth

The effect of repeated prescribed burning on long term growth of Pinus ponderosa in northern Arizona was examined. Fire treatments for hazard reduction were initiated in 1976, acid growth was evaluated in 1988 for fire rotations of 1, 2, 4, 6, 8, and 10 years. Dendroecological analysis shows that there were only small changes in tree growth (compared to controls) in the first few years after the initial fire treatment despite large fuel reductions and thinning, and that annual precipitation was positively correlated with growth. Moderate changes in growth relative to that of control trees were apparent after 1984. The 1-, 2-, 8-, and 10-year treatments had lower growth than controls after this date, while 4- and 6-year treatments had slightly higher growth. Although additional data are needed to determine long term growth effects in the longer fire rotations, a fire treatment interval of 4 to 6 years appears to provide adequate fuel reduction without reducing long term growth in Southwestern P. ponderosa forests.

Predicting effects of global warming on growth and mortality of upland oak species in the midwestern United States: a physiologically based dendroecological approach

This study combined an ecophysiological model and dendroecological analyses to evaluate potential effects of global warming on the physiology, growth, and mortality of white oak (Quercusalba L.) and black oak (Quercusvelutina Lam.) in the Ohio River region. The model integrated data for ecophysiology of oak species, site attributes, and daily temperature and precipitation to model nonlinear responses of stomatal conductance (gs), net photosynthesis (Pnet), and woody respiration (Rw) to variations in temperature and soil water content. Relationships between modeled physiological response indices and actual white and black oak annual radial growth indices were evaluated by regression analyses, using growth and weather data for the period 1900–1987 for seven upland oak–hickory forests. Modeled physiological response indices explained 40–60% of variation in radial growth indices. To evaluate the effects of global warming, daily temperature values for the period 1900–1987 were increased by 2 or 5 °C, without changing precipitation values, and physiological response indices were computed. Model indices generated in warming simulations were entered into dendroclimatic regression models calibrated under conditions without any warming to predict radial growth under warming scenarios. Under the warming scenarios, OAKWBAL predicted a substantial increase in growing season Rw, but little change in growing season Pnet. Warming merely shifted the period of near-maximal Pnet earlier in the growing season, without changing its duration. However, this result was somewhat dependent upon the ability of leaf-out phenology to track changes in temperature regime. The net effect of increased Rw, with little change in Pnet, was a reduction in radial growth and a higher frequency of years with climatic conditions stressful to oaks on upland sites. A historical association between severe drought and increased incidence of oak growth decline and mortality indicated that global warming could increase the incidence of decline and mortality in oak populations on upland sites similar to those in this study.

Ground Frost Restriction of Subarctic Picea Abies Forest in Northern Sweden. A Dendroecological Analysis

A subarctic population of Picea abies ssp. obovata in northern Sweden was retrospectively analyzed dendroecologically: tree-ring chronology (A.D. 1773–1989) and age structure. Additionally, recent ...

Dendroecological analysis of a longleaf pine Pinus palustris forest in Mississippi

A climate model with time varying parameters was fit to longleaf pine (Pinus palustris) tree rings collected from the proposed Harrison Research Natural Area of the De Soto National Forest in southern Mississippi. The purpose of the analysis was to determine if any unexpected disturbances had influenced the growth of the trees. Current September temperature, August rainfall and February Palmer Drought Severity Index (PDSI) were found jointly to be the best variables in the model to predict growth. August rain had a constant significant effect on growth and February PDSI was not significant except between the years 1968–1983. It was concluded that the Harrison area has been in equilibrium for the past 50 years since no apparent outside influences have caused the trees to become less sensitive to climate. Thus, the forest is a good candidate for a Research Natural Area.

Ground Frost Restriction of Subarctic Picea Abies Forest in Northern Sweden. A Dendroecological Analysis

Ground Frost Restriction of Subarctic Picea Abies Forest in Northern Sweden. A Dendroecological Analysis

Old-growth red spruce communities in the mid-Appalachians

Old-growth stands of red spruce (Picea rubens) were sampled at the only four localities in the mountains of southwestern Virginia and central West Virginia where examples of such are known to exist. Based upon mean ages (±SE) of cored trees, sampled stands ranged in age from 164±18 to 201±10 yr. Dendro-ecological (tree-ring) analysis showed a marked decline in growth of trees at three localities during the late 1800s, followed by recovery to previous levels of growth within two decades. This growth-trend decline generally coincides with a period of extensive mortality of red spruce reported to have occurred in central West Virginia. Basal area of trees ≥2.5 cm DBH ranged from 35.4 to 46.1 m2/ha. These figures are considerably lower than those recorded at earlier dates for similar old-growth stands in the Appalachians, which suggests that a general decline has occurred over the last half-century.