Forest Management Treatments Research Articles

Curse or blessing? Local elites in Joint Forest Management in India’s Shiwaliks

This article suggests that local elites play an instrumental role – either with positive or negative consequences – in shaping struggles for power over processes and outcomes of participatory forest management interventions, when implemented in communities characterized by social hierarchies. We show how the contrasting outcomes of joint forest management in two case study villages cannot be attributed to institutional reform, but appear to be caused largely by differences in the role assumed by local elites. The evidence indicates that institutional reform itself does not guarantee changes in the actual management of natural resources. Rather, vested interests at the local level and among State actors may continue to shape events while working within or beyond the new institutional landscape. On the basis of the results of our case studies, the article poses the hypothesis that a network theory of social capital could be a useful way of analyzing such diverse outcomes of similar institutional reforms implemented in relatively similar communities. We conclude by arguing that attempts at institutional reform at the level of the community in hierarchical societies should proceed with modest expectations, and an eye for the incentives facing local elites and the implementing and facilitating State actors.

Soil CH4 fluxes response to understory removal and N-fixing species addition in four forest plantations in Southern China

CH4 is one of the most important greenhouse gases, and mainly comes from soils in forest ecosystems. The objective of this study was to determine the effects of forest management practices such as understory removal and N-fixing species (Cassia alata) addition, on soil CH4 fluxes in four forest plantations in southern China. Fluxes of CH4 were measured in Eucalyptus urophylla plantation (B1), Acacia crassicarpa plantation (B2), 10-native-species-mixed plantation (B3), and 30- native-species-mixed plantation (B4) stands using the static chamber method in Southern China. Four forest management treatments, including (1) understory removal and replacement with C. alata (UR+CA); (2) understory removal only (UR); (3) C. alata addition only (CA); and (4) control without any disturbances (CK), were applied in the four forest plantations. The results showed that plantation types had a significant effect on soil CH4 fluxes. B1 and B2 tended to be CH4 consumers, while B3 and B4 inclined to be CH4 producers. UR decreased CH4 fluxes by providing a more optimal soil temperature and moisture regime for microorganism community and increasing substrate mineralization. However, CA enhanced CH4 fluxes in B1 and B2 for N-fixing function of C. alata while lowered CH4 fluxes in B3 and B4. Soil CH4 flux rate was significantly related to soil temperature and moisture conditions in the top 10-cm soil layer. Furthermore, the quality of substrates, such as Soil Organic Carbon (SOC) and mineral N might also be important driving factors for CH4 fluxes. This study improved our understanding on CH4 fluxes in plantations under different management practices such as UR and CA.

Water yield changes as a result of silvicultural treatments in an oak ecosystem

Interception loss represents an important factor of water balance. The reduction of interception loss through silvicultural treatments to the benefit of water yield is very important for countries with large periods of limited rainfall like Greece. In the context of climate change and its possible effects on water availability, oak ecosystems can play a significant role in water production, as they comprise the largest part of the forested area in Greece. The objective of this study is to investigate the relationships between water interception changes, as a result of different forest management treatments, and water yield. For this reason, experimental watersheds have been established for the study of the hydrological impacts of thinning and clearcutting in an oak ecosystem in northern Greece. Two watersheds were used as control while different combinations of thinning (removal 50% of basal area) and clearcutting treatments were used in the other three study watersheds. Canopy annual interception amounted for 9.0%, 6.7% and 1.8% of the total precipitation in the untreated, thinned and clearcut plots respectively. The practiced thinning and clearcutting operations increased the available amount of water by a mean annual average of 13.2 mm and 42.8 mm respectively compared to the control watersheds. The total water surplus represented 29.5%, 30.9% and 33.9% of the average annual precipitation for the control, thinned and clearcut plot respectively. Surface flow was very low even during large rainfall events, possibly due to the soil and bedrock attributes and the topography of the area. Analogous silvicultural treatments can increase water availability but they should incorporate reduced-impact logging and skidding practices and thus cause the least possible soil disturbance, by carefully selecting the best suited wood harvesting systems and methods.

Effects of understory removal and N-fixing species seeding on soil N2O fluxes in four forest plantations in southern China

The magnitude, temporal, and spatial patterns of nitrous oxide (N2O) fluxes in plantations are still largely unknown; however, they are crucial for our understanding and management of global greenhouse gas emissions. The objective of this study was to determine the effects of forest management practices, such as the understory removal and nitrogen (N)-fixing species (Cassia alata [C. alata]) seeding, on soil N2O fluxes in four forest plantations in southern China. Fluxes of N2O were measured in a Eucalyptus urophylla plantation (EUp), an Acacia crassicarpa plantation (ACp), 10 native species-mixed plantation (Tp), and 30 native species-mixed plantation (THp) by a static chamber method from June 2007 to May 2008 in Guangdong province, China. Four forest management treatments, including understory removal and replacement with C. alata (UR+CA), understory removal only (UR), C. alata seeding only (CA), and (4) control without any disturbances (CK), were applied in the four forest plantations. The results showed that N2O fluxes were higher under UR treatment as compared to CK in EUp (16.9 μg m−2 h−1), ACp (16.3 μg m−2 h−1), Tp (14.4 μg m−2 h−1), and THp (14.4 μg m−2 h−1) during the study period. Soil N2O fluxes under CA treatment tended to be enhanced in EUp (18.1 μg m−2 h−1), ACp (18.3 μg m−2 h−1), Tp (19 μg m−2 h−1), and THp (16.6 μg m−2 h−1), having higher values in CA than in CK. There were positive relationships between N2O fluxes and soil temperature (P < 0.01), soil moisture (P < 0.01), and nitrate (NO3)–N concentrations (P < 0.05). Our results indicated that soil NO3–N, soil temperature, and moisture are the primary controlling variables for soil N2O fluxes. The present study improved our understanding of soil N2O fluxes in forest plantations under different management practices.

Diversity of naturally regenerating tree species in the overstorey layer of Larix kaempferi plantations and abandoned broadleaf coppice stands in central Japan

Forestry, Vol. 83, No. 3, 2010. doi:10.1093/forestry/cpq011 For Permissions, please email: journals.permissions@oxfordjournals.org Advance Access publication date 12 May 2010 Introduction One-quarter of Japan’s land area is occupied by plantations (10.4 million ha in 2001). In many plantations, active management or ‘tending’ (weeding and thinning) of the forests has been abandoned due to declining timber prices and an aging workforce. Consequently, the extension of plantation rotation periods has become an increasingly common means of producing more valuable timber in maturing stands and of maintaining biological diversity. Species diversity in forests is strongly affected by the kinds of forest management interventions employed, and the impacts of these interventions can have a marked and variable effect on the structure and functioning of different forest ecosystems (e.g. plantations, coppice forests). Studying the effects of forest management is considered an important aspect of sustainable ecological forest management because it promotes an understanding of the relationship between stand structure and species composition (Kerr, 1999; Cummings and Reid, 2008). Since stand age can also influence the species composition of forest stands, a chronosequence approach is increasingly being applied to studies of how stand age and stand management practices influence stand composition (Hunt et al., 2003; Nagaike et al., 2006a). Plantations would be designated for ecological restoration when it is recognized that they were established on sites that are unsuitable for timber production and where there is a need for conserving biological diversity (Zerbe, 2002; Masaki et al., 2004; Cummings and Reid, 2008). The change in species composition associated with stand age in plantations differs with that in naturally regenerated stands since different regeneration processes (i.e. planting vs natural regeneration) and tending procedures (e.g. weeding and thinning) are employed. Stand age of plantations is important because it is directly related to the amount of timber produced and the cutting rotation employed in a landscape. When considering the requirements of ecological restoration initiatives, it is important to set the end points of either natural or historical conditions as a target for the restored forests (Stanturf, 2005) and establish baseline data for the composition of naturally regenerated tree species in the subject plantations. In addition, as another end point, the plantations should also be compared with natural forests as the end points, which represent the natural condition of forests in a region. Forest management (e.g. directly removing trees and shrubs by thinning and weeding) is known to affect each stratum of the forest differently (Nagaike et al., 2003; Diversity of naturally regenerating tree species in the overstorey layer of Larix kaempferi plantations and abandoned broadleaf coppice stands in central Japan

Effects of Forest Management on Postfledging Survival of Rose-breasted Grosbeaks (Pheucticus ludovicianus)

ABSTRACT. Many studies have examined the effects of forest fragmentation and management on songbird nesting success, but few have quantified postfledging survival, which is a critical component of population productivity. In 2005–2006, we estimated daily postfledging survival of Rose-breasted Grosbeaks (Pheucticus ludovicianus) by radiotracking 42 fledglings in forest fragments that had been managed by single-tree selection, by diameter-limit harvest, or as reference (not harvested for at least 25 years). Survival probability over the 3-week fledgling period was 0.62, and 86% of total fledgling mortality occurred during the first week out of the nest. Despite large differences in forest structure between forest management treatments, there was no effect of forest treatment on fledgling survival. Date of fledging, shrub cover, and patch size also had limited influence on fledgling survival. For all sites combined, females produced an estimated 0.23–0.37 recruiting daughters per year for the worst- and best...

Immediate effects of logging, mounding and removal of logging residues and stumps on coarse woody debris in managed boreal Norway spruce stands

Wood fuel production has increased remarkably, but its environmental effects within the forest ecosystem have not yet been studied much. We investigated the immediate effects of two series of forest management treatments, which produce timber and forest chips, on the volume and decay classes of coarse woody debris (CWD). One of the treatment series included logging and residue harvesting (LRH) and mounding (M), while the other series included LRH and mounding combined with stump harvesting (MSH). We hypothesized that, i) LRH reduces CWD, excluding stumps; ii) the more intense the soil preparation treatment is, M vs. MSH, the more CWD is destroyed; iii) both LRH and soil preparation treatments (M and MSH) reduce the occurence of snags, highly decayed CWD and deciduous CWD in particular. Ten sample plots in mature managed Norway spruce (Picea abies (L.) H. Karst.) dominated forests were located in Southern Finland. The total volume of CWD on the sample plots was measured three times: before and after LRH, and after M or MSH. LRH significantly decreased the volume of snags and the combined volume of snags and logs. MSH significantly decreased the total volume of CWD, while M had no significant effect on the volume of CWD. The middle and highly decayed CWD were destroyed most easily in the treatments.

Wildlife responses to thinning and burning treatments in southwestern conifer forests: A meta-analysis

After a century of fire suppression, conifer forests in the western United States have dramatically departed from conditions that existed prior to Euro-American settlement, with heavy fuel loads and an increased incidence of wildfire. To reduce this threat and improve overall forest health, land managers are designing landscape-scale treatments that strategically locate thinning and burning treatments to disrupt fuel continuity, allowing managed wildfires to burn the remaining area. A necessary step in designing and evaluating these treatments is understanding their ecological effects on wildlife. We used meta-analysis to compare effects of small-diameter removal (thinnings and shelterwoods) and burning treatments, selective harvesting, overstory removal (including clearcutting), and wildfire on wildlife species in southwestern conifer forests. We hypothesized that small-diameter removal and burning treatments would have minimal effects on wildlife compared to other treatments. We found 33 studies that met our criteria by (1) comparing density or reproductive output for wildlife species, (2) using forest management or wildfire treatments, (3) implementing control-impact or before-after control-impact design using unmanaged stands as controls, and (4) occurring in Arizona or New Mexico ponderosa pine (Pinus ponderosa) or mixed conifer (Abies/Picea/Pinus) forest. The 22 studies suitable for meta-analysis occurred ≤20 years post-treatment on sites <400ha. Small-diameter harvest and burning treatments had positive effects but thin/burn and selective harvest treatments had no detectable effect on most small mammals and passerine bird species reported in studies; overstory removal and wildfire resulted in an overall negative response. We examined foraging guild responses to treatments; ground-foraging birds and rodents had no strong response. Aerial-, tree-, and bole-foraging birds had positive or neutral responses to the small-diameter removal and burning treatments, but negative responses to overstory removal and wildfire. Small-diameter removal and burning treatments as currently being implemented in the Southwest do not negatively impact most of the wildlife species in the studies we examined in the short-term (≤10 years). We believe a combination of treatments in a patchy arrangement across the landscape will result in the highest diversity and density. We recommend that managers implement thinning and burning treatments, but that future research efforts focus on long-term responses of species at larger spatial scales, use reproductive output as a more informative response variable, and target species for which there is a paucity of data.

Facilitating the Transition from Passive to Active Community Forest Management: Lessons from Rapti Zone, Nepal

This paper demonstrates that a transition from passive to active management of community forest is possible by adopting joint learning processes among local forest user groups, forest officials and local non?governmental service providers. Such an approach has the potential to address several issues that underlie and characterise passive management namely: underutilisation of forest, protection oriented forest management, overstocked forest (dense) vis?a?vis deficit in supply of forest products, and poorly designed silvicultural practices. Passive management is attributed mainly to the poor planning of forest management, inadequate and restrictive forest inventory guidelines and limited recognition of the forest management knowledge of locally trained resource persons. We present evidence of the processes and outcomes of active management being promoted by Community Forest User Groups (CFUGs) in Nepal. The transition to active forest management is demonstrated through an assessment of revisions made in the community forest Operational Plans (OP). Key revisions identified include, among others: defining objectives of forest management considering people's choices and locality factors, site?specific forest management treatments, development of product utilisation plans, provisions for Non?timber Forest Products (NTFPs) management and conservation of biodiversity and water resources. Full text is available at the ForestAction websiteDOI: http://dx.doi.org/10.3126/jfl.v8i2.2308 Journal of Forest and Livelihood 8(2) February 2009 pp.51-66

The spatiotemporal forest cover changes in Köprülü Canyon National Park (1965 - 2008) in Turkey

Analyzing the historical legacy of forest structure and its temporal changes is paramount to design future forest management interventions in preparing an effective forest management plan in national parks. In this study, forest cover type maps prepared in 1965, 1984 and 2008 were digitized using geographic information systems and spatial database was built for nearly 36000 ha Koprulu Canyon National Park. Spatial data bases for three periods were used to determine temporal and spatial (number, size and spatial distributions of patches) changes of forest resources using FRAGSTATS™ program. The results indicated clear changes in the temporal and spatial dynamics of land cover/forest cover. Mixed forests increased about 151.7% (1570.7 ha) like agricultural and urban areas 39.8% (777.5 ha) and productive forests (crown closure > 10%) increased 21.9% (2838.8 ha) too, while other open lands decreased about 27.5% (1326.3 ha) and 459 ha pure cedar stands entirely converted mostly to the degraded and mixed forests from 1965 to 2008. In terms of spatial configuration, analysis of the metrics revealed that landscape structure in study area has changed substantially over the 43-year study period, resulting in fragmentation of the landscape as the total number of patches increased from 238 to 672 and mean patch size drop from 1615.0 ha to 425.3 ha markedly between 1965 and 2008. Geographic Information Systems (GIS) coupled with fragmentation analysis has a powerful role in analyzing spatiotemporal dynamics of forest landscape for effective national park planning.

Arthropods as bioindicators of sustainable forest management, with a focus on plantation forests

Here we review the bioindicator potentials of several arthropod groups in forest management. First, we describe the indicator potentials of frequently used arthropod groups in general forest management, and then evaluate ecosystem function and plural taxonomic groups to infer forest biodiversity. We then review indicator potentials of arthropod groups to explore the ecological consequences of forest management practices. Different arthropod groups respond differently to forest management. Ants, carabid beetles, and spiders often respond to local-scale, disturbance-induced vegetation development caused by thinning and can be used to infer the ecological suitability of forest management treatments. Dung beetles and moths respond to habitat alterations caused by forest fragmentation and can indicate the suitability of landscape-level forest management techniques. Butterflies and cerambycid beetles respond highly positively to the presence of herbaceous plants and understory trees and can be used to infer the integrity of thinning treatments in forest management. Syrphid flies, which are strong flyers associated with vegetation complexity, can be used as bioindicators of landscape-level forest management practices. Monitoring regulatory service providers may also help when designing forest management practices. We propose using arthropod bioindicator groups to effectively design and assess ecologically sustainable management plans for both natural and plantation forests.

Quantifying the protective function of a forest against rockfall for past, present and future scenarios using two modelling approaches

Following a major rockfall event in 1987, two types of protection measures were taken in the village Saint Martin le Vinoux (French Alps). Firstly, technical measures using civil engineering were installed, and secondly, a forest management intervention to increase its protection was carried out. This study aims to assess whether this intervention was successful in the sense that it improved the protective function of the forest. We evaluated the rockfall risk for the situation of 1987 (before the intervention), today and the future, using model simulations with past, present and future vegetation cover scenarios. To increase the meaningfulness of our results, we used two different models, called Rockfor.NET, which is a rapid one-dimensional rockfall forest evaluation tool, using simple slope and forest characteristics and RockyFor, a process based on three-dimensional rockfall simulation model that takes the barrier effect of individual trees explicitly into account. Both models correctly predicted that the forest was not capable of stopping rocks from the 1987 rockfall event. Further, both models indicate an increase of the number of rocks reaching the base of the slope from 1987 onwards. RockyFor shows an increase from 11% in 1987 to 19% in 2086. Rockfor.NET shows an increase from 26% in 1987 to 56% in 2086. We conclude that a second attempt to increase the protective function of the forest should aim at restoring a dense coppice stand.

Evaluation of a mechanistic approach to mixedwood modelling

Mixed conifer–broadleaf forests (mixedwoods), covering more than a third of the productive forest landbase in BC, are highly valuable both as sources of fibre and as areas rich in biodiversity. In recognition of the multiple benefits of this forest type, management paradigms have transitioned from a focus on promoting conifer plantations in mixedwood areas to the management of intimate mixtures. The exceptionally dynamic growth properties and species interactions in mixedwood forests present a challenge for projecting the growth and development of different types of mixedwoods and their response to different silviculture systems. Here we evaluate the ability of a mechanistic forest growth model (FORECAST) to project patterns of stand growth and dynamics in two mixedwood forest types subjected to different silvicultural treatments. Model output is compared against field measurements from long-term silviculture trials in the Sub Boreal Spruce (SBS)—18 years, and Interior Cedar Hemlock (ICH)—10 years, biogeoclimatic zones in British Columbia, Canada. FORECAST was able to reproduce patterns of growth response in both mixedwood forest types with reasonable accuracy. An analysis of the simulated relative impact of light and nutrient competition on growth dynamics and treatment response is provided. Results suggest that competition for both light and nutrients are important factors in the dynamics of these mixedwood forest types and that long-term response data and modelling are required to adequately assess the rotation-length effects of treatments on stand development. The analysis described herein provides a level of confidence for the use of the model as a decision-support tool in these ecosystem types, but more validation work should be conducted across a range of different mixedwood forest types and management interventions as long-term datasets become available. Key words: FORECAST, mixedwood management, model testing, process-based model, resource competition

Forest management treatments, tree resistance, and bark beetle resource utilization in ponderosa pine forests of northern Arizona

We show experimentally that forest restoration treatments that used thinning to reduce ponderosa pine density near Flagstaff, Arizona decreased the percentage of trees with successful bark beetle attacks induced by beetle community response to a Dendroctonus brevicomis pheromone. Underlying mechanisms for the beneficial effect of restoration treatments on tree resistance to bark beetles included stimulation of resin defenses. Resin flow after phloem wounding was greater in full and partial restoration treatments than the control in the first and second year after treatment. Five bark beetle species, Ips pini, D. brevicomis, D. valens, D. adjunctus, and D. frontalis, colonized and produced brood in the trees. There was a negative correlation between resin volume and number of brood that emerged from the bole. Niche breadth of the bark beetle species over bole positions was widest for I. pini and narrowest for D. brevicomis.

Habitat alteration increases invasive fire ant abundance to the detriment of amphibians and reptiles

Altered habitats have been suggested to facilitate red imported fire ant (Solenopsis invicta) colonization and dispersal, possibly compounding effects of habitat alteration on native wildlife. In this study, we compared colonization intensity of wood cover boards by S. invicta among four forest management treatments in South Carolina, USA: an unharvested control (>30 years old); a partially thinned stand; a clearcut with coarse woody debris retained; and a clearcut with coarse woody debris removed. Additionally, we compared dehydration rates and survival of recently metamorphosed salamanders (marbled salamanders, Ambystoma opacum, and mole salamanders, A. talpoideum) among treatments. We found that the number of wood cover boards colonized by S. invicta differed significantly among treatments, being lowest in the unharvested forest treatments and increasing with the degree of habitat alteration. Salamanders that were maintained in experimental field enclosures to study water loss were unexpectedly subjected to high levels of S. invicta predation that differed among forest treatments. All known predation by S. invicta was restricted to salamanders in clearcuts. The amount of vegetative ground cover was inversely related to the likelihood of S. invicta predation of salamanders. Our results show that S. invicta abundance increases with habitat disturbance and that this increased abundance has negative consequences for amphibians that remain in altered habitats. Our findings also suggest that the presence of invasive S. invicta may compromise the utility of cover boards and other techniques commonly used in herpetological studies in the Southeast.

Effects of timber harvest on breeding-site selection by gray treefrogs ( Hyla versicolor)

Despite numerous studies showing reduced amphibian abundance and diversity following habitat modification, little is known about the mechanisms causing these observed patterns. We examined the effects of four experimental forest management treatments on breeding-site selection by gray treefrogs ( Hyla versicolor) in Missouri. Our study of four management treatments included a clearcut with high amounts of coarse woody debris (CWD), a clearcut with lower amounts of CWD, a partial timber cut, and an uncut control. We placed five plastic wading pools in each treatment replicated at three sites and found that gray treefrogs laid significantly more eggs in the clearcuts (low-CWD 77,185 eggs; high-CWD 51,990 eggs) than in either the partial (13,553 eggs) or the control (14,068 eggs) treatments. We further examined the importance of distance between breeding sites and mature forest habitat by placing cattle tanks 50 m into clearcuts, 10 m into clearcuts, 10 m into forests, and 50 m into forests. Gray treefrogs oviposited eggs more frequently in the clearcut-edge tanks (17 occasions) than in the clearcut (7), forest (8), or forest-edge (3) tanks, but eggs were not counted. Despite the preference for open canopy breeding sites, oviposition was less in sites located farther from forest edges. Male captures at the tanks indicated that males also preferred clearcut treatments but were not inhibited by the 50 m distance from the forest edge. Although reduced canopy cover over breeding ponds may benefit tadpoles, logging operations should avoid excessively isolating aquatic habitat from forested uplands.

Modelling tree mortality by bark beetle infestation in Norway spruce forests

Disturbances play a major role in forest ecosystems, they are main constituents of forest dynamics and are often a relevant driver in forest management decisions. The European Spruce Bark Beetle ( Ips typographus L. Col. Scol.) is one of the major biotic disturbances in Norway spruce ( Picea abies (L.) Karst.) forests. In this contribution a sub-model of disturbances by I. typographus was developed and integrated in the existing hybrid forest patch model PICUS v1.4. The new disturbance sub-model builds on a recently developed phenology model for risk assessment of outbreaks of I. typographus (PHENIPS) and elements from an existing predisposition assessment system (PAS). Model parameterisation was based on data from 28 Norway spruce stands in Austria. In a preliminary model evaluation a comprehensive sensitivity analysis at sites along an elevation gradient in the Eastern Alps is presented. Sensitivity over the elevation gradient was found to be highest and strongly non-linear with regard to the thermal environment. Furthermore, in accordance with general expectations and observations simulated damages were high under colline and submontane conditions and strongly decreased over the elevation transect. Based on the results of the simulation experiments it is concluded that the presented model is a promising tool to analyse the dynamic interaction of disturbances by I. typographus, environmental conditions and forest structure as affected by natural forest development and management interventions. Limitations of the model and possible approaches for extensive validation against empirical damage data are discussed.

Headwater Riparian Microclimate Patterns under Alternative Forest Management Treatments

Abstract Management of headwater streams and their riparian zones has included the implementation of forested riparian buffers, which are intended to protect ecological processes (such as microclimate) and biota, but the appropriate widths for these buffers have been widely debated. We measured the magnitude and extent of microclimatic gradients associated with headwater streams in mature unmanaged forests, and determined whether these patterns were maintained in clearcut harvested units with and without a 30 m-wide riparian buffer on each side of the stream. We measured air temperature, soil temperature, and relative humidity between 1 and 70 m from the stream in five replicate blocks of three treatments each in western Oregon. Results indicated the strongest stream effect on air temperature and relative humidity to be within 10 m of the stream in all management treatments at 3:00 pm, and gradients were evident to 20 m in the forested treatment. The clearcut was significantly hotter (air and soil) and drier than either the riparian buffer or the forest treatments at 3:00 pm. The riparian buffer and forest had similar microclimates at all distances from the stream, suggesting that the 30-m buffer adequately protected the riparian microclimatic gradient. We hypothesize that the strong stream effect on microclimate in the riparian zone serves a critical role in mitigating the influence of microclimatic “edge effects” associated with the forest-clearcut edge. Biota dependent on cool, humid microclimates provided by riparian zones will benefit from the implementation of riparian buffers in harvest units.

Using Forest Inventory Data To Assess Fisher Resting Habitat Suitability In California

The fisher (Martes pennanti) is a forest-dwelling carnivore whose current distribution and association with late-seral forest conditions make it vulnerable to stand-altering human activities or natural disturbances. Fishers select a variety of structures for daily resting bouts. These habitat elements, together with foraging and reproductive (denning) habitat, constitute the habitat requirements of fishers. We develop a model capable of predicting the suitability of fisher resting habitat using standard forest vegetation inventory data. The inventory data were derived from Forest Inventory and Analysis (FIA), a nationwide probability-based sample used to estimate forest characteristics. We developed the model by comparing vegetation and topographic data at 75 randomly selected fisher resting structures in the southern Sierra Nevada with 232 forest inventory plots. We collected vegetation data at fisher resting locations using the FIA vegetation sampling protocol and centering the 1-ha FIA plot on the resting structure. To distinguish used and available inventory plots, we used nonparametric logistic regression to evaluate a set of a priori biological models. The top model represented a dominant portion of the Akaike weights (0.87), explained 31.5% of the deviance, and included the following variables: average canopy closure, basal area of trees <51 cm diameter breast height (dbh), average hardwood dbh, maximum tree dbh, percentage slope, and the dbh of the largest conifer snag. Our use of routinely collected forest inventory data allows the assessment and monitoring of change in fisher resting habitat suitability over large regions with no additional sampling effort. Although models were constrained to include only variables available from the list of those measured using the FIA protocol, we did not find this to be a shortcoming. The model makes it possible to compare average resting habitat suitability values before and after forest management treatments, among administrative units, across regions and over time. Considering hundreds of plot estimates as a sample of habitat conditions over large spatial scales can bring a broad perspective, at high resolution, and efficiency to the assessment and monitoring of wildlife habitat.

Drought effects on fine-root and ectomycorrhizal-root biomass in managed Pinus oaxacana Mirov stands in Oaxaca, Mexico

The effects of a severe drought on fine-root and ectomycorrhizal biomass were investigated in a forest ecosystem dominated by Pinus oaxacana located in Oaxaca, Mexico. Root cores were collected during both the wet and dry seasons of 1998 and 1999 from three sites subjected to different forest management treatments in 1990 and assessed for total fine-root biomass and ectomycorrhizal-root biomass. Additionally, a bioassay experiment with P. oaxacana seedlings was conducted to assess the ectomycorrhizal inoculum potential of the soil for each of the three stands. Results indicated that biomasses of both fine roots and ectomycorrhizal roots were reduced by almost 60% in the drought year compared to the nondrought year. There were no significant differences in ectomycorrhizal and fine-root biomass between the wet and dry seasons. Further, the proportion of total root biomass consisting of ectomycorrhizal roots did not vary between years or seasons. These results suggest that both total fine-root biomass and ectomycorrhizal-root biomass are strongly affected by severe drought in these high-elevation tropical pine forests, and that these responses outweigh seasonal effects. Forest management practices in these tropical pine forests should consider the effects of drought on the capacity of P. oaxacana to maintain sufficient levels of ectomycorrhizae especially when there is a potential for synergistic interactions between multiple disturbances that may lead to more severe stress in the host plant and subsequent reductions in ectomycorrhizal colonization.