Forest remnants in the Long Point region, Southern Ontario: Tree species diversity and size structure (original) (raw)
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Forest management can significantly affect both the diversity and spatial patterning of understory vegetation. However, few studies have considered both diversity and spatial patterning at a stand scale. Our objective was to evaluate the effects of forest management on understory plant communities in northern hardwood forests and assess the processes governing differences in species composition, diversity, and spatial patterns. We sampled understory vegetation (all species Ͻ2 m tall) and percentage of light transmission levels in three forest types in 12 mesic northern hardwood stands in northern Wisconsin and the Upper Peninsula of Michigan, USA: old-growth, undisturbed forests; even-aged forests resulting from clearcut logging (ϳ65-85 yr old); and uneven-aged forests with recent selective logging.
Robinson Woods Preserve is a 32.4 ha forest in southwestern Michigan that had been cleared and cropped and then abandoned sometime in the 1920s, at which time secondary succession was initiated. The objective of this study is to describe the current tree species composition and the succes-sional changes that led to it. In 2011 and 2012, the T-square method and the point-centered quarter method were used to determine the current structure and composition of the forest. Data from these methods were compared with similar data from two earlier studies of the same area conducted in 1972 and 1986. Between 1972 and 2011–2012, shade-intolerant trees of Sassafras albidum and Prunus serotina had decreased in importance by 22% and 82%, respectively, while shade-tolerant trees of Fagus grandifolia, Quercus rubra and Acer rubrum had increased by 26,790%, 352% and 21%, respectively. Between 1986 and 2011–2012, the density of most species had declined, except for trees of Fagus grandifolia, whose density had increased by 44%. In addition, trees of S. albidum had been reduced in importance to a subdominant role in the presence of A. rubrum and Q. rubra. Seedling and sapling densities by size class show that most of the canopy trees are reproducing themselves. However, no Ulmus americana and Fraxinus americana trees larger than 45 cm dbh were encountered , the former having been killed by Dutch elm disease and the latter by the emerald ash borer. Over the 90 years since abandonment, a hardwood forest has developed, one in which pioneer tree species have been replaced in part by shade-tolerant trees. Based on these results, it is expected that the future forest will likely become an American beech–sugar maple forest, especially in the absence of periodic fire.
Understory Species Patterns and Diversity in Old-Growth and Managed Northern Hardwood Forests
Ecological Applications, 2002
Forest management can significantly affect both the diversity and spatial patterning of understory vegetation. However, few studies have considered both diversity and spatial patterning at a stand scale. Our objective was to evaluate the effects of forest management on understory plant communities in northern hardwood forests and assess the processes governing differences in species composition, diversity, and spatial patterns. We
The Forestry Chronicle, 2007
Species composition estimated from forest resource inventory (FRI) was validated using field data collected in 136 stands in Nipissing Forest (Ontario, Canada). FRI- and field-based species composition matched in 54% and 56% of cases using stand count and area coverage, respectively. Possible causes of discrepancy between FRI- and field-based species composition are discussed. Low level of agreement between FRI and field data indicated a need for more extensive studies on FRI validation prior to its use for forest management planning. Key words: forest resource inventory, FRI, forest unit, photo-interpretation, timber cruise
Preservation of old‐growth forests: a case study of Big Timber Park, Whistler, BC
Canadian Geographies / Géographies canadiennes, 2008
This paper explores the concepts of old‐growth forests, preservation and natural disturbance and demonstrates how contemporary biogeographic theory contributes to successful preservation of old‐growth forests. The case study analyzes the composition, structure, age and growth histories of trees in Big Timber Park, Whistler, British Columbia. Composition. The structure of the forest was diverse and tree ages ranged from 122 to 305 years. The densities of large old Douglas‐fir, shade‐tolerant trees and all snags are indicative of old‐growth forests; however, maximum tree diameters and densities of large snags and logs do not meet quantitative criteria for old‐growth forests. The abundance of tree regeneration and understory vegetation are relatively low. We conclude that some aspects of Big Timber Park are transitional between the mature and old‐growth stages of forest development. In the future, fine‐scale canopy gaps caused by tree senescence and interactions among insects, pathogen...
Canadian Journal of Forest Research, 2015
We undertook a gap analysis of how protected areas represent the tree-species diversity within the Canadian boreal forest, as measured from Forest Resource Inventory (FRI) maps. We used a new compilation of Forest Resource Inventory designed to support ecological analyses over large areas and across jurisdictional boundaries. The analysis was stratified into four analytical regions determined by terrestrial ecozones. We calculated the relative abundance of species within regions, developed rarity criteria, and evaluated the relative abundances and prevalence of rare species. We characterized representation gaps when the abundance of a tree species in protected areas within an analytical region differed markedly (by more than a factor of 2) from the expectation, calculated as the product of regional abundance and the proportional area protected. Most species were well represented in the most speciesdiverse region (n = 33), the Boreal Shield in eastern Canada, due apparently to a large number of relatively small protected areas in the southern part of the region. Some marked gaps existed in the more species-depauperate western zones, notably for montane conifers in the Boreal Plains. As is common for species abundance distributions, as few as five species accounted for 90% of total abundance in each zone. Relatively rare species were more numerous. Mostly associated with southern temperate or hemiboreal forests, these reached their highest prevalence and abundance in the managed forests of the Boreal Shield. Our work identified some gaps in representation in the protected areas network of Canada in western Canada, substantiates the use of species distribution mapping based on FRI data to inform conservation planningincluding the identification of high conservation biodiversity elements for forest certificationand demonstrates the need for improved vegetation mapping in National Parks.
Habitat Diversity in Uneven-aged Northern Hardwood Stands: A Case Study
2000
Habitat characteristics were quantified in an empirically balanced uneven-aged northern hardwood stand in central New York. Canopy structure, wildlife trees, downed woody material, low cover, and richness and abundance of understory vegetation were assessed. High vertical structural diversity and low horizontal patchiness were associated with the single-tree selection system. Downed logs and wildlife trees were spatially well distributed, and cavities at a range of heights and sizes were documented. Application of a selection cutting decreased total canopy closure, but maintained high vertical structural diversity and an even distribution of foliage among canopy strata. Cutting reduced the number of wildlife trees, but increased low cover, shade-intolerant understory vegetation, and the abundance and complexity of downed woody material. This study provides quantifiable evidence of the diversity of habitat characteristics associated with a balanced stand structure and uniform spatial arrangement of different sized trees in uneven-aged northern hardwood stands.
The Forestry Chronicle, 2003
Harvesting techniques that retain structural elements of the original forest may help to preserve the characteristic ecological features and biological diversity of old-growth forests. Harvesting with advance regeneration protection (HARP) is one such technique practised in the Lake Abitibi Model Forest of northeastern Ontario on peatland sites. In this system, winter harvesting operations clear trees in strips about 5–7 m wide and using a minimum diameter limit cut extract trees from the adjacent residual forest rows, 5–9 m wide. In order to assess the effectiveness of HARP in retaining forest structure, we quantified forest and understorey structural features in 24 1.65-ha plots spanning a wide range of forest retention, including clearcuts, three levels of HARP, and the edge and interior of unharvested forest (logging had occurred 2.5–3.5 years before the study). Mean tree age, diameter, and height in HARP forests in all cases exceeded 68% of the mean values found in unharvested ...
Temporal changes in species composition of mixedwood stands in northwest New Brunswick: 1946–2008
Canadian Journal of Forest Research, 2010
Patterns of softwood (SW) – hardwood (HW) change from 1946 to 2006 in 32 unharvested mixedwood (MW) stands in northern New Brunswick were analyzed using aerial photographs (1946, 1966, 1982, and 2006), sampled, and related to disturbance and stand conditions. Five stand development patterns were identified based on 1946 SW content (70%–80%, termed SW versus 30%–60%, termed MW) and change in SW content from 1946 to 2006 (SW-stable, SW-declining, MW-fluctuating, MW-stable, or MW-declining). Species composition was surprisingly changeable over this 60-year period, with change in SW content varying from +18% to –62%. High canopy cover reduction from 1946 to 1966 resulted from balsam fir ( Abies balsamea (L.) Mill.) mortality due to old age and a 1950s spruce budworm ( Choristoneura fumiferana Clem.) outbreak plus birch ( Betula sp.) dieback. SW-stable stands that maintained SW composition from 1946 to 2006 (+7%) had more red spruce ( Picea rubens Sarg.) than all other classes in which S...
Forest Science, 2004
On high quality growing sites in West Virginia, shade intolerant tree species have increased in importance in third-generation forests following clearcutting. We investi- gated the effect of tree species canopy position on the Shannon-Weiner Diversity Index (H'), Pielou's evenness index (0, and species richness (S) using a chronosequence of 13 clearcuts. Two to 26 yr after clearcutting, tree species diversity significantly decreased from 2.07 to 1.83, and evenness decreased from 0.80 to 0.71 while species richness was maintained. As the number of years since harvesting increased, the importance value of oaks (Quercus L.), hickories (Carya Nutt.), American beech (Fagus grandifolia Ehrh.), sugar maple (Acersaccha- . rum Marsh.), and black birch (Betula lenta L.) decreased while the importance of yellow-poplar (Liriodendron tulipifera L.) increased. In these mixed-species stands with stratified canopies, species importance in overstory versus understory canopy layers was the be...