Small Clearcuts Research Articles

Application of a three-dimensional model for assessing effects of small clear-cuttings on radiation and soil temperature

A three-dimensional model Mixfor-3D of soil–vegetation–atmosphere transfer (SVAT) was developed and applied to estimate possible effects of tree clear-cutting on radiation and soil temperature regimes of a forest ecosystem. The Mixfor-3D model consists of several closely coupled 3D sub-models describing: forest stand structure; radiative transfer in a forest canopy; turbulent transfer of sensible heat, H 2O and CO 2 between ground surface and the atmospheric surface layer; evapotranspiration of ground surface vegetation and soil; heat and moisture transfer in soil. The model operates with the horizontal grid resolution, 2 m × 2 m; vertical resolution, 1 m and primary time step, 1 h. The model was tested against meteorological data obtained at a small clear-cutting area in Otterbach in central Germany during summer 2005. The meteorological data including air temperature and humidity, precipitation, solar radiation, wind speed and direction, soil temperatures at 10 and 20 cm depth were measured by five automatic stations within the clear-cut area. One reference station was placed about 100 m from the clear-cut inside the forest stand. Comparisons of modelled and measured solar radiation fluxes and soil temperature profiles showed that the model adequately describes the spatial heterogeneity and dynamics of these variables under different weather conditions. The model can be used to explore solar radiation and soil temperature patterns within heterogeneous forest plots, with applications to various silvicultural tasks.

Partial and clearcut harvesting of dry Douglas-fir forests: Implications for small mammal communities

Dry Douglas-fir ( Pseudotsuga menziesii) forests offer a wide range of timber and non-timber values, which may benefit from a balanced timber harvest by variable retention systems with conservation of biodiversity. A major component of biodiversity are forest floor small mammal communities whose abundance and diversity serve as ecological indicators of significant change in forest structure and function from harvesting activities. This study was designed to test the hypotheses that abundance, reproduction, and survival of (i) the southern red-backed vole ( Myodes gapperi, formerly Clethrionomys gapperi), will decline; (ii) the deer mouse ( Peromyscus maniculatus), will be similar; and (iii) the meadow vole ( Microtus pennsylvanicus) and northwestern chipmunk ( Tamias amoenus), will increase, with decreasing levels of tree retention. Small mammal populations were live-trapped from 1994 to 1997 in replicated sites of uncut forest, 20% and 50% volume removal by single tree selection, 20%, 35%, and 50% patch cuts based on openings of 0.1–1.6 ha, and small 1.6 ha clearcuts in Douglas-fir forest near Kamloops, British Columbia, Canada. M. gapperi dominated the small mammal community, starting with an abundance of 74–98 animals/ha with mean values ranging from 33 to 51 animals/ha. In the two post-harvest years, abundance, reproduction, and survival of M. gapperi populations were consistently similar among uncut forest and the various levels of tree retention. Thereafter, M. gapperi was seldom found on the small clearcuts. M. pennsylvanicus, T. amoenus, and P. maniculatus occurred predominantly in clearcut sites. As with other types of forest disturbance, responses to our treatments were species-specific. The most striking result was the high abundance and productivity of M. gapperi populations in a dry forest ecosystem, a novel result for this bio-indicator species of closed-canopy forest conditions. At least with respect to small mammals, the retention systems studied seem to enable timber extraction and maintenance of mature forest habitat in these dry fir ecosystems.

Effects of strip and single-tree selection cutting on birds and their habitat in a southwestern Quebec northern hardwood forest

In the northern hardwood forest of northeastern North America, ecological and social perceptions call for forest management systems using reduced-impact silviculture such as single-tree selection cutting and small clearcuts. When applied over large areas, single-tree selection cut and small clearcut systems are likely to generate different local habitat structures and spatio-temporal habitat distribution in the landscape. This study assessed the effects of strip cutting and single-tree selection cutting on forest breeding birds when extensively applied in a northern hardwood forest in southwestern Quebec, a decade after timber harvest. Birds were surveyed twice during two consecutive breeding seasons by 270 point counts, equally distributed in a single-tree selection cut forest, a strip cut forest, and an untreated forest. At each point count, habitat features and horizontal heterogeneity of these features were measured. Managed forest habitats had a much more developed understory, fewer snags and more downed woody debris. Horizontal heterogeneity was higher in the strip cut forest and lower in the single-tree selection cut forest. Of the 20 bird species analyzed, 13 showed a difference in abundance between at least two of the three treatments. Dendroica pensylvanica was mostly seen in the treated forests while Dendroica virens and Seiurus aurocapillus were more abundant in the untreated forest. Pheucticus ludovicianus was twice as abundant in the strip cut forest, while Catharus ustulatus was more frequently observed in the single-tree selection cut forest. Habitat vertical structure variables that differed among the three treatments were the most correlated with bird abundance. The results of this study support the use of a mix of silvicultural systems within the same forest in order to sustain habitat diversity for maintaining the regional avian cortege.

Satellite Change Detection of Forest Harvest Patterns on an Industrial Forest Landscape

Abstract Multiple dates of Landsat Thematic Mapper (TM) imagery were analyzed to compare a decade of forest harvest activity in northern Maine's industrial forest. Unsupervised clustering on three-date sequences of Normalized Difference Vegetation Index classified the harvest type and time period when change occurred. Problematic clusters were reclassified using the Normalized Difference Moisture Index, which improved the detection of light partial harvests. The procedure classified clearcuts and partial cuts in all time periods with at least 80% agreement with 250 reference sample points. Patch characteristics of the harvest areas revealed a shift from large clearcuts in the late 1980s and early 1990s to fewer and smaller clearcuts in the middle to late 1990s. By the late 1990s, large clearcuts (>40 ha) were eliminated, and partial cuts increased in size. Partial cuts affected more land area than did clearcuts in all time periods. Comparison of harvest patches between the two largest landowners in the study area revealed significant differences in the number and distance between clearcut harvest areas. The trends in decreasing clearcut harvesting practices over the past decade appear to have been influenced by forestry legislation, according to the results of this study and an independent report by the Maine Forest Service. The changing harvest patterns on the landscape were detectable on time-series satellite imagery. FOR. SCI. 49 (3):341–353.

Natural regeneration of Picea abies on small clear-cuts in SE Norway

The objective was to study the influence of vegetation cover, humus depth, microrelief and distance to seed tree edge on natural regeneration of Norway spruce ( Picea abies (L.) Karst.) in five small clear-cuts on bilberry woodland in southeastern Norway. The impact of the vegetation was considered at tree different scales: at the growing point, in the nearest square decimetre around the seedlings and at a 1 m 2 scale. Most of the regeneration (95%) developed in 1996, after a rich seed year in 1995. The microhabitat was of crucial importance to seedling establishment. Litter, Sphagnum spp. and Polytrichum commune were good substrates for establishment, while areas dominated by Deschampsia flexuosa, Dicranum spp. and Pleurozium schreberi had very few seedlings. Seedling survival after five growing seasons was slightly better in litter than in Sphagnum and other mosses, but the differences were not statistically significant. Increasing humus depth had a positive influence on regeneration, probably due to shallow soils at the sites. Even though depressions covered only 4.9% of the ground, 24.1% of the seedlings occurred here. Survival was, however, lower in depressions than in the other microrelief classes. Distance to the seed tree edge had a significant influence on establishment, with more seedlings establishing close to the edge.

Forest management and public perceptions — visual versus verbal information

Forest and landscape management measures have impacts on the amenity value of forests. People may have certain attitudes towards management, in particular near urban areas. The aim of this study was to evaluate the impacts on scenic beauty and recreational value of five different management practices: small clear cutting, thinning, removal of undergrowth, natural state, and traditionally managed cultural landscape. In order to compare visual perceptions with preconceptions, two evaluation methods, visual presentation (pictures produced by image-capture technology) and verbal questions were used. Scenic beauty and recreational value were assessed from slides in which management measures were presented by the pairwise comparison technique. The results indicate that scenic beauty and recreational preferences differ considerably from each other. In the study areas, small clear cuttings had the most positive effect on scenic beauty and natural state had most positive effect on recreational value. Furthermore, preconceptions concerning different silvicultural measures did not consistently correspond to perceptions based on the assessment of visual images. This fact supports the use of visual presentation methods in future preference studies as well as in participatory forest planning projects.

Home range and habitat use of male ruffed grouse in managed mixed oak and aspen forests

Ruffed grouse ( Bonasa umbellus) occupy many areas of the eastern and southeastern United States where oak ( Quercus sp.) is the dominant forest type. However, most research on grouse habitat requirements and populations has taken place in Lake States aspen ( Populus sp.) forests. We captured and radiotagged male grouse to determine spring and summer home range sizes and habitat use on a 1120 ha experimental forest management area in central Pennsylvania. The dominant forest types were aspen-black cherry and mixed oak. The management area was divided into two sections, one which was managed with a short-rotation clearcutting scheme and one that was left unmanaged. Breeding season and summer home ranges of male ruffed grouse were similar to those observed in the Midwest (5.0–9.4 ha), and did not appear to differ between managed and unmanaged habitats. However, habitats used differed between the managed and unmanaged areas. Male grouse on the managed area used aspen-black cherry and mixed oak sapling stands more than expected during both the breeding season and summer. Pole-sized and sawtimber aspen stands in the unmanaged area were used more than expected during breeding and summer seasons. Male ruffed grouse avoided mixed oak sawtimber stands, which comprised 62% and 47% of the available habitat in the unmanaged area and managed area, respectively. Our results demonstrated that southern mixed oak stands can be managed effectively for ruffed grouse with small (1 ha) clearcuts.

Soil nutrient and vegetation response to patch clear-cutting of an aspen forest near Meadow Lake, Saskatchewan

Alternate silviculture systems, such as small patch clearcuts, may become important in the development of sustainable forest management strategies in aspen forests. A study was initiated in a 64-yr-old trembling aspen (Populus tremuloides Michx.) stand in Meadow Lake Provincial Park, Saskatchewan to determine changes in nutrient dynamics and secondary succession following patch clear-cutting. One hectare replicated patch cuts were logged in the winter of 1993–1994. There was no site preparation following harvest. Annual vegetation, regeneration and soil and plant nutrient data were collected annually, 1 yr prior to, and 3 yr following harvest. Aspen regeneration was 48 375 stems ha−1 2 yr after treatment. Stand (alpha) diversity of the understory was not affected by harvesting, although annual species turnover (beta diversity) increased slightly after harvest. There was an increase in aspen foliar nitrogen (N) for 2 yr following harvest. Soil nutrient concentrations did not differ between patch cut and unharvested plots except total potassium (18% lower in the LFH of the harvested treatments 3 yr after harvesting). Small patch cuts with the litter horizon kept intact may be appropriate for aspen-dominated stands in the boreal mixed wood to minimize ecological disturbance while maintaining aesthetics within a park setting. Key words: Ammonium, aspen regeneration, diversity, nitrate, plant community structure, soil productivity

Transience of deer wintering areas

Fidelity of white-tailed deer (Odocoileusvirginianus) to wintering areas was examined in west-central New Brunswick. Wintering areas were located and mapped during aerial surveys in 1975 and 1987–1989. Of 99 wintering areas identified in 1975, 42 were unoccupied 13 years later. Small wintering areas (<50 ha) were more likely to be unoccupied in the subsequent survey than larger ones (>100 ha). Forest cutting had a profound effect on transience of wintering areas. Small clearcuts within a wintering area increased the likelihood of deer use. Wintering areas that were completely clear-cut were likely to be abandoned.

Avian Use of Habitat Configurations Created by Forest Cutting in Southeastern Wyoming

Timber harvest in western forests initially interrupts large expanses of oldgrowth forest with smaller clearcuts. Although the vegetation within the remaining oldgrowth is still present and intact, there is an increase in forest edges and a reduction in the continuity of the original forest. We compared avian species composition and abundance in four pairs of sites, each pair having an uncut site and one fragmented by small clearcuts in southeastern Wyoming. Fragmented stands were interrupted with strip or patch clearcuts. The abundance of species was also compared among the habitat configurations present on these sites such as forest interiors, meadow edges and clearcuts. Of 16 bird species, Brown Creepers (Certhia americana) and Hermit Thrushes (Catharus guttatus) were the most negatively influenced by fragmentation; Pine Siskins (Carduelis pinus) were the most positively influenced by fragmentation. The distribution of birds among forest interiors and edges suggested the responses to fragmentation were not generally mirrored by preferences or avoidance of forest edges and interiors. The effect of fragmentation may result from the loss of resources from clearcutting or preferences for the type of habitat adjacent to the forest stand (meadows or clearcuts).

Effets de coupes de dimensions restreintes sur l'abondance des populations d'oiseaux nicheurs en milieu boréal

The objective of this study was to evaluate the effects of small clearcuts on breeding bird communities found in adjacent forest stands. The study was conducted in a deer yard of the Duchenier Wildlife Preserve located in the boreal balsam fir-yellow birch ecological domain of eastern Quebec. The balsam fir-northern white cedar stands of the deer yard had been treated by strip cutting 2 years before the study. Total abundance of nesting passerines in stands adjacent to 60-m-wide strip cuttings was greater (P = 0.10) than in similar control unlogged stands. The establishment of shrub strata within the strip probably provided an additional food source for shrub- and ground-feeding species without significantly affecting canopy-feeding species.

Avian community response to small-scale habitat disturbance in Maine

The effects of small clearcuts (1–8 ha) on avian communities in the forest of eastern Maine were studied using point counts during spring 1978 – 1981. Surveys were conducted in uncut (control) and clear-cut (treatment) plots in three stand types: conifer, hardwood, and mixed growth. We used a mark –recapture model and its associated jackknife species richness estimator [Formula: see text], as an indicator of avian community structure. Increases in estimated richness [Formula: see text] and Shannon–Weaver diversity (H′) were noted in the treated hardwood and mixed growth, but not in the conifer stands. Seventeen avian species increased in relative abundance, whereas two species declined. Stand treatment was associated with important changes in bird species composition. Increased habitat patchiness and the creation of forest edge are hypothesized as causes for the greater estimates of richness and diversity.

Woodland caribou and forestry in Northern Ontario, Canada

Expansion of logging in remote Ontario boreal forest requires mitigation of effects on woodland caribou. Three examples of caribou-forestry interaction are reviewed. In two, caribou were apparently displaced from peripheral portions of their winter range by logging. In the third, caribou disappeared when exposed to: logging in a central third of their winter range; increased deer density, and; a probable increase in predation. In all cases there is no evidence of human harvest. The literature plus experience in Ontario suggest the following mitigative techniques: protection of winter concentration areas, significant calving areas and traditional migration routes from logging; directing timber harvest to forest stands of least value to caribou; restricting disturbance to one large clearcut in a peripheral portion of range rather than dispersing it over a large portion as several small clearcuts; modified site preparation and regeneration, and; restricted road access. Research is required on the effect of forestry on caribou with and without mitigation, and on causes for effects observed.

Effects of clearcutting and site preparation on herpetofauna of a North Florida flatwoods

Drift-fence sampling for 1 year yielded information on effects of clearcutting and site-preparation intensity on flatwoods herpetofauna in northern Florida. Sampling occurred in a naturally regenerated 40-year-old slash pine forest and two adjacent 3–4-year-old clearcuts subjected to different site treatments. Four drift-fence array (16 fences) in the forest captured totals of 6266 amphibians (15 species) and 230 reptiles (21 species). From an equal number of arrays in both the minimum- and maximum-treatment clearcuts, amphibian captures totalled 592 (9 species) and 758 (11 species), respectively, and reptile captures totalled 196 (19 species) and 85 (14 species), respectively. Clearcutting and site-preparation treatments did not affect amphibian species richness, but reptile species richness was lower in the maximum-treatment clearcut, due to the absence of some arboreal lizard and snake species. Clearcutting reduced amphibian abundance tenfold by affecting reproductive success. Reptile abundance was reduced by maximum site preparation but not by minimum site preparation. Arboreal lizard populations were severely reduced by clearcutting. Herpetofaunal biomass was not affected by clearcutting and site preparation, but the biomass was apportioned differently among taxonomic groups. The minimum-treatment clearcut had higher snake biomass and lower anuran biomass than the other two sites, whereas the maximum-treatment clearcut had lower lizard biomass than the other two sites. Reptile communities in flatwoods would be favored by site-preparation practices that minimized site disturbances and maximized presence of logging debris. Responses of amphibian communities seemed to be dependent upon availability of water. Overall herpetofaunal diversity would be greatest in an area containing a mosaif of small clearcuts, cypress domes, and different-aged pine stands.

THE POTENTIAL FOR INCREASING STREAMFLOW FROM SIERRA NEVADA WATERSHEDS1

ABSTRACTThe Sierra Nevada produces over 50 percent of California's water. Improvement of water yields from the Sierra Nevada through watershed management has long been suggested as a means of augmenting the state's water supply. Vegetation and snowpack management can increase runoff from small watersheds by reducing losses due to evapotranspiration, snow interception by canopy, and snow evaporation. Small clearcuts or group selection cuts creating openings less than half a hectare, with the narrow dimension from south to north, appear to be ideal for both increasing and delaying water delivery in the red fir‐lodgepole pine and mixed‐conifer types of the Sierra west slope. Such openings can have up to 40 percent more snow‐water equivalent than does uncut forest. However, the water yield increase drops to 1/2‐2 percent of current yield for an entire management unit, due to the small number of openings that can be cut at one time, physical and management constraints, and multiple use/sustained yield guidelines. As a rough forecast, water production from National Forest land in the Sierra Nevada can probably be increased by about 1 percent (0.6 cm) under intensive forest watershed management. Given the state of reservoir storage and water use in California, delaying streamflow is perhaps the greatest contribution watershed management can make to meeting future water demands.