Recovery Of Forest Ecosystems Research Articles

Soil depth and recovery interval mediate soil water repellency under different forest types and fire intensity levels in China: Evidence for ecosystem resiliency

Soil water repellency (SWR) is a physical phenomenon whereby the surface of soil particles cannot be, or resists being, moistened by water. The recovery process of fire-induced SWR can provide important evidence for ecosystem resilience, but most existing studies ignored this process. Prescribed burning is a widely used method to reduce the risk of fire and fuel. However, prescribed fires can increase SWR, reducing infiltration and increasing overland flow and subsequent soil erosion. In order to understand the ecosystem resilience process from fire-induced SWR, soil samples were collected before and after prescribed burning. Four different forest types in the Hunan province of China were studied. Soil samples at four different soil depths (0–5, 6–10, 11–15, and >15 cm) and four time intervals (3, 30, 180, and 360 d) after burning at different intensities were collected. No significant difference in SWR was found among the four forest types, but the SWR of soil in plantations was stronger than that in secondary forests before fire. Most soil samples showed slightly increased SWR after burning, SWR increasing with fire intensity. Surface soil (0–5 cm) SWR showed greater sensitivity to fire disturbance than subsurface soil (>5 cm). SWR had a smaller scope of influence and shorter recovery period in burned secondary forests. Although SWR recovered over time, recovery was slower with increasing fire intensity. SWR always recovered to pre-fire levels given sufficient time. Our study revealed the recovery process of SWR, and explored the temporal and spatial mechanisms of forest ecosystem recovery after prescribed burning.

Soil health indicators for monitoring forest ecological restoration: a critical review

Forest restoration is considered among the most affordable and effective practices to address ecosystem and biodiversity loss and mitigate the impacts of human‐induced global change. Soils are intrinsically complex systems that mediate and regulate multiple processes and functions vital for forest ecosystem restoration. Although monitoring soil attributes are critical for evaluating the success of forest restoration projects, research, and development of soil function indicators are still limited. Here, we have reviewed the most commonly reported soil indicators in forest restoration research and their recovery trajectory on a global scale. We also identified and discussed less frequently used indicators that have the potential for monitoring ecosystem recovery. We found that soil indicators have considerably increased in the literature. However, research is regionally concentrated, and a significant proportion of publications neither considered reference ecosystems (41%) nor provided basic information about soil types (<21%). The most reported indicator types were chemical (76%) (e.g., soil carbon, nitrogen, and pH). A significant proportion of the studies (46%) performed long‐term evaluations (>15 years) of indicators. The majority of the indicators tended to resemble the levels of the reference ecosystem in the long term, with a few exceptions (e.g., water content and bulk density). We identified several less used but more integrative indicators with great potential for monitoring forest ecosystem recovery (e.g., aggregate stability, oxidizable carbon, soil respiration, and enzyme activity). Our results emphasize the need to effectively develop standardized soil health indicators to monitor ecosystem recovery under different conditions and expand their use in underrepresented regions.

Remote-Sensing Monitoring of Postfire Vegetation Dynamics in the Greater Hinggan Mountain Range Based on Long Time-Series Data: Analysis of the Effects of Six Topographic and Climatic Factors

The frequency of forest fires is increasing under global climate change, and forest fires can cause devastating disturbances to forest systems and varying degrees of recovery of forest ecosystems after a disaster. Due to the different intensity of forest fires and forest systems, and in particular the fact that forest ecological recovery is influenced by many topographical and climatic factors, the process of postfire vegetation recovery is unclear and must be studied in depth. In this study, the Greater Hinggan Mountain Range was taken as the study area. Based on the Moderate Resolution Imaging Spectroradiometer (MODIS) and Landsat time-series images acquired from 2000 to 2018, this study used the spatiotemporal data fusion method to construct reflectance images of vegetation with a relatively consistent growth period to study the vegetation restoration after forest fires. The vegetation restoration was characterized by disturbance index (DI) values, which eliminated phenological influence. Six types of topography and climatic factors (elevation, aspect, slope; temperature, precipitation, and wind speed) were coupled with DI. Through single-factor analysis of variance and multiple comparison statistical methods, it was found that there was a significant relationship between the six factors and DI, which indicated those factors had a significant impact on the restoration of forest vegetation in burned areas. The results will be useful as a reference for future monitoring and management of forest resources.

A triple tree-ring constraint for tree growth and physiology in a global land surface model

Abstract. Annually resolved tree-ring records extending back to pre-industrial conditions have the potential to constrain the responses of global land surface models at interannual to centennial timescales. Here, we demonstrate a framework to simultaneously constrain the representation of tree growth and physiology in the ORCHIDEE global land surface model using the simulated variability of tree-ring width and carbon (Δ13C) and oxygen (δ18O) stable isotopes in six sites in boreal and temperate Europe. We exploit the resulting tree-ring triplet to derive integrative constraints for leaf physiology and growth from well-known mechanistic relationships among the variables. ORCHIDEE simulates Δ13C (r=0.31–0.80) and δ18O (r=0.36–0.74) better than tree-ring width (r<0.55), with an overall skill similar to that of a tree-ring model (MAIDENiso) and another isotope-enabled global vegetation model (LPX-Bern). The comparison with tree-ring data showed that growth variability is not well represented in ORCHIDEE and that the parameterization of leaf-level physiological responses (stomatal control) to drought stress in the temperate region can be constrained using the interannual variability of tree-ring stable isotopes. The representation of carbon storage and remobilization dynamics emerged as a critical process to improve the realism of simulated growth variability, temporal carryover, and recovery of forest ecosystems after climate extremes. Simulated forest gross primary productivity (GPP) correlates with simulated tree-ring Δ13C and δ18O variability, but the origin of the correlations with tree-ring δ18O is not entirely physiological. The integration of tree-ring data and land surface models as demonstrated here should guide model improvements and contribute towards reducing current uncertainties in forest carbon and water cycling.

How mycorrhizas can help forests to cope with ongoing climate change?

The ongoing climate change have multi-faceted effects not only on metabolism of plants, but also on the soil properties and mycorrhizal fungal community. Under climate change the stability of the entire forest ecosystems and the carbon balance depend to a large degree on the interactions between trees and mycorrhizal fungi. The main drivers of climate change are CO<sub>2</sub> enrichment, temperature rise, altered precipitation patterns, increased N deposition, soil acidification and pollutants, ecosystem fragmentation and habitat loss, and biotic invasion. These drivers can impact mycorrhizal community directly and indirectly. We discussed the influence of each driver on mycorrhizal community and outlined how mycorrhizas play an important role in the resilience and recovery of forest ecosystems under climate change, by mitigating detrimental effects of CO<sub>2</sub> enrichment, temperature rise, drought, lack of nutrients, soil acidification, pollutants, pests, and diseases. Conservation of the overall biodiversity in forest ecosystems as well as providing the most favourable conditions for the development of mycorrhizae can contribute to increasing the resilience of forest ecosystems to climate change.

Direct seeding of Oreomunnea mexicana, a threatened tree species from Southeastern Mexico

Compared to enrichment planting techniques, direct seeding may represent a viable low-cost method to ensure the conservation and recovery of forest ecosystems. However, it is necessary to identify the environmental factors that affect seed germination and seedling establishment in order to improve the success of this technique. It has been suggested that the establishment of Oreomunnea mexicana (Juglandaceae), a threatened tropical montane cloud forest tree species, is associated with microsites of high soil moisture. We assessed seedling emergence in O. mexicana through direct seeding in a secondary forest and characterized the microenvironmental conditions of the sowing microsite. We also assessed the effect of seed hydration on seedling emergence and evaluated the effect of soil moisture content and seed hydration in O. mexicana seed germination and seedling emergence under laboratory conditions. Seedling emergence was lower in the field than in the laboratory (37 vs. 42 %, respectively). At microsite level, seedling emergence correlated positively with soil moisture content but negatively with vegetation cover. After 11 months, 52 % of the emerged seedlings still survived. Under laboratory conditions, seedling emergence did not differ significantly between hydrated and non-hydrated seeds (43.2 ± 0.52 vs. 40.3 ± 0.51 %, respectively), but did between high and low soil moisture contents (80 ± 0.18 vs. 3.5 ± 0.085 %, respectively). With appropriate soil moisture and vegetation cover conditions, O. mexicana seed introduction into secondary forest is a reliable technique. However, the method could be improved by protecting the seedlings from physical damage.

Application of lime (CaCO3) to promote forest recovery from severe acidification increases potential for earthworm invasion

The application of lime (calcium carbonate) may be a cost-effective strategy to promote forest ecosystem recovery from acid impairment, under contemporary low levels of acidic deposition. However, liming acidified soils may create more suitable habitat for invasive earthworms that cause significant damage to forest floor communities and may disrupt ecosystem processes. We investigated the potential effects of liming in acidified soils where earthworms are rare in conjunction with a whole-ecosystem liming experiment in the chronically acidified forests of the western Adirondacks (USA). Using a microcosm experiment that replicated the whole-ecosystem treatment, we evaluated effects of soil liming on Lumbricus terrestris survivorship and biomass growth. We found that a moderate lime application (raising pH from 3.1 to 3.7) dramatically increased survival and biomass of L. terrestris, likely via increases in soil pH and associated reductions in inorganic aluminum, a known toxin. Very few L. terrestris individuals survived in unlimed soils, whereas earthworms in limed soils survived, grew, and rapidly consumed leaf litter. We supplemented this experiment with field surveys of extant earthworm communities along a gradient of soil pH in Adirondack hardwood forests, ranging from severely acidified (pH<3) to well-buffered (pH>5). In the field, no earthworms were observed where soil pH<3.6. Abundance and species richness of earthworms was greatest in areas where soil pH>4.4 and human dispersal vectors, including proximity to roads and public fishing access, were most prevalent. Overall our results suggest that moderate lime additions can be sufficient to increase earthworm invasion risk where dispersal vectors are present.

A Tour de Force by Hawaii's Invasive Mammals: Establishment, Takeover, and Ecosystem Restoration through Eradication

Invasive mammals, large and small, have irreversibly altered Hawaii’s ecosystems in numerous cases through unnatural herbivory, predation, and the transmission of zoonotic diseases, thereby causing the disproportionate extinction of flora and fauna that occur nowhere else on Earth. The control and eradication of invasive mammals is the single most expensive management activity necessary for restoring ecological integrity to many natural areas of Hawai‘i and other Pacific Islands, and has already advanced the restoration of native biota. Science applications supporting management efforts have been shaped by longstanding collaborative federal research programs over the past four decades. Consequently, feral goats have been removed from &gt;1,358 km2, and feral pigs have been removed from &gt;723 km2 of lands in Hawai‘i, bringing about the gradual recovery of forest ecosystems. The exclusion of other non-native ungulates and invasive mammals is now being undertaken with more sophisticated control techniques and fences. New fence designs are now capable of excluding feral cats from large areas to protect endangered native waterfowl and nesting seabirds. Rodenticides that have been tested and registered for hand and aerial broadcast in Hawai‘i have been used to eradicate rats from small offshore islands to protect nesting seabirds and are now being applied to montane environment of larger islands to protect forest birds. Forward-looking infrared radar is also being applied to locate cryptic wild ungulates that were more recently introduced to some islands. All invasive mammals have been eradicated from some smaller islands, resulting in the restoration of some ecosystem processes such as natural forest regeneration, but changes in other processes such as fire regimes and nutrient cycling remain more difficult to reverse at larger landscape scales. It may soon be possible to manage areas on larger islands to be free of invasive mammals at least during seasonally important periods for native species, but at the same time, new mammal introductions continue to occur.

How Can Social Safeguards of REDD+ Function Effectively Conserve Forests and Improve Local Livelihoods? A Case from Meru Betiri National Park, East Java, Indonesia

The National REDD+ (Reducing Emissions from Deforestation and Forest Degradation-Plus) Strategy in Indonesia highlights the importance of local participation and the reform of land tenure in the success of forest conservation. National parks are a main target area for REDD+. National parks in Indonesia have been suffering from forest destruction and conflicts between governments and local communities. This study investigated: (1) the historical process of developing the REDD+ project in collaboration with multiple stakeholders including government authorities, local NGOs, and local people; (2) the social and economic impacts of the REDD+ project on local people; and (3) the local awareness of and motivations to participate in the REDD+ project in Meru Betiri National Park in Indonesia. Interviews of stakeholders including village leaders, NGO staff, and park staff were conducted to obtain an overview of the REDD+ project in the national park. Interviews with a questionnaire were also conducted among randomly selected heads of households who participated or did not participate in the REDD+ project and lived adjacent to the national park. Our analysis revealed that participants in the project obtained the right to use illegally harvested bared lands for intercropping while planting trees to recover forest ecosystems inside the national park. This opportunity could have contributed to a drastic increase in income, particularly for economically disadvantaged people, and to the recovery of forest ecosystems. Although local people did not fully recognize the meaning of REDD+ or carbon credits, they were enthusiastic to join in managing and patrolling forests because of their satisfaction with the income generated by the national park. However, the challenge is how both the recovery of forests and income generation from the project can be maintained in a situation of insufficient funding from donors and unsettled arguments about the benefit of sharing carbon credits with local people.

Effect of anthropogenic disturbances on biomass and carbon storage potential of a dry tropical forest in India

The forests of Chhattisgarh are very well known for its species richness, diversity, biomass, carbon stock and productivity. The present study was carried out at Katghora forest division under Bilaspur circle of Korba district, Chhattisgarh considering three sites viz., least, moderately and highly disturbed site to estimate biomass and carbon storage in relation to anthropogenic disturbances. For collection of data quadrats were selected under stratified random sampling design. For enumeration of tree and saplings ten quadrats of 10 m × 10 m were laid and each species counted separately. The tree density varies from 100-510 stems ha-1 across study sites. Total biomass in the present study was between 127.69 t ha-1 and 227.71 t ha-1. Total above ground biomass was between 111.20 t ha-1 and 199.42 t ha-1, whereas total below ground biomass varied from 16.49-28.29 t ha-1, respectively. The total carbon storage across the sites were ranged from 55.125 to 98.548 t C ha-1 found higher under least disturbed site and lowest under medium disturbed site. Carbon storage pattern according to girth class followed the similar trend of distribution as was in the case of biomass. It has least proportion in small girth class and maximum storage under the higher girth class. It is evident from the study that disturbances have significant impact on density, vegetation diversity, biomass accumulation and carbon storage pattern. Conservation affords are required to control on disturbances and for the natural recovery of forest ecosystem.

Combined effect of atmospheric nitrogen deposition and climate change on temperate forest soil biogeochemistry: A modeling approach

Atmospheric N deposition is known to severely impact forest ecosystem functioning by influencing soil biogeochemistry and nutrient balance, and consequently tree growth and overall forest health and biodiversity. Moreover, because climate greatly influences soil processes, climate change and atmospheric N deposition must both be taken into account when analysing the evolution of forest ecosystem status over time.Dynamic biogeochemical models have been developed to test different climate and atmospheric N deposition scenarios and their potential interactions in the long term. In this study, the ForSAFE model was used to predict the combined effect of atmospheric N deposition and climate change on two temperate forest ecosystems in France dominated by oak and spruce, and more precisely on forest soil biogeochemistry, from today to 2100. After a calibration step and following a careful statistical validation process, two atmospheric N deposition scenarios were tested: the current legislation in Europe (CLE) and the maximum feasible reduction (MFR) scenarios. They were combined with three climate scenarios: current climate scenario, worst-case climate scenario (A2) and best-case climate scenario (B1). The changes in base saturation and inorganic N concentration in the soil solution were compared across all scenario combinations, with the aim of forecasting the state of acidification, eutrophication and forest ecosystem recovery up to the year 2100.Simulations highlighted that climate had a stronger impact on soil base saturation, whereas atmospheric deposition had a comparative effect or a higher effect than climate on N concentration in the soil solution. Although deposition remains the main factor determining the evolution of N concentration in soil solution, increased temperature had a significant effect. Results also highlighted the necessity of considering the joint effect of both climate and atmospheric N deposition on soil biogeochemistry.

Machine learning an audio taxonomy: Quantifying biodiversity and habitat recovery through rainforest audio recordings

We present a set of tools for semi-supervised classification of ecosystem health in Meso-American tropical dry forest, one of the most highly endangered habitats on Earth. Audio recordings were collected from 15-year-old, 30-year-old and old growth tropical dry forest plots in the Guanacaste Conservation Area, Costa Rica, on both nutrient rich and nutrient poor soils. The goals of this project were to classify the overall health of the regenerating forests using markers of biodiversity. Semi-supervised machine learning and digital signal processing techniques were explored and tested for their ability to detect species and events in the audio recordings. Furthermore, multi-recorder setups within the same vicinity were able to improve detection rates and accuracy by enabling localization of audio events. Variations in species' and rainforest ambient noise detection rates over time were hypothesized to correlate to biodiversity and hence the health of the rainforest. By comparing levels of biodiversity measured in this manner between old growth and young dry forest plots, we hope to determine the effectiveness of reforestation techniques and identify key environmental factors shaping the recovery of forest ecosystems.

Evidence of recovery of Juniperus virginiana trees from sulfur pollution after the Clean Air Act.

Using dendroisotopic techniques, we show the recovery of Juniperus virginiana L. (eastern red cedar) trees in the Central Appalachian Mountains from decades of acidic pollution. Acid deposition over much of the 20th century reduced stomatal conductance of leaves, thereby increasing intrinsic water-use efficiency of the Juniperus trees. These data indicate that the stomata of Juniperus may be more sensitive to acid deposition than to increasing atmospheric CO2. A breakpoint in the 100-y δ(13)C tree ring chronology occurred around 1980, as the legacy of sulfur dioxide emissions declined following the enactment of the Clean Air Act in 1970, indicating a gradual increase in stomatal conductance (despite rising levels of atmospheric CO2) and a concurrent increase in photosynthesis related to decreasing acid deposition and increasing atmospheric CO2. Tree ring δ(34)S shows a synchronous change in the sources of sulfur used at the whole-tree level that indicates a reduced anthropogenic influence. The increase in growth and the δ(13)C and δ(34)S trends in the tree ring chronology of these Juniperus trees provide evidence for a distinct physiological response to changes in atmospheric SO2 emissions since ∼1980 and signify the positive impacts of landmark environmental legislation to facilitate recovery of forest ecosystems from acid deposition.

Woodland salamanders as metrics of forest ecosystem recovery: a case study from California's redwoods

Woodland (Plethodontid) salamanders occur in huge numbers in healthy forests in North America where the abundances of many species vary along successional gradients. Their high numbers and trophic role as predators on shredder and decomposer arthropods influence nutrient and carbon pathways at the leaf litter/soil interface. Their extreme niche conservatism and low vagility offer further advantages to the use of these salamanders as metrics of forest ecosystem condition. Mill Creek is a 103 km2 commercially logged redwood forest watershed acquired as parkland where original primary forest is being restored. This study evaluated woodland salamanders as metrics of seral recovery at Mill Creek. Surface counts and body condition were examined in four sets of stands, two early seral, one mature, and one of primary forest (never harvested old‐growth). Later seral sites were closer to the coast where fog increased available moisture; younger sites were further inland at higher elevations where fog was reduced. We distinguished the effects of geography and succession using ANCOVA with a PCA‐derived landscape covariate. Both geography and succession increased counts of California Slender Salamanders (Batrachoseps attenuatus); advancing succession alone indicated increased counts of Ensatina (Ensatina eschscholtzii). Means and variances in body condition of these two species were lower in older stands; for the Del Norte salamander (Plethodon elongatus) only the means were lower. Coastal proximity increased mean body condition in E. eschscholtzii, but with P. elongatus it was the opposite. We modeled surface counts and body condition along environmental gradients associated with succession. The counts and body condition in two of three species when taken together suggested that the increased structural complexity in late‐seral forest stands supported larger populations that appeared to be competing for limited resources and, thus, likely have greater population fitness than those in younger forests. B. attenuatus and E. eschscholtzii proved to be viable metrics of advancing succession with their numbers and body condition providing readily quantifiable measures of ecosystem recovery at Mill Creek.

Influence of road reclamation techniques on forest ecosystem recovery

Road reclamation has emerged as an integral part of ecological restoration strategies, particularly on public lands. However, there are no consistent techniques for how road reclamation should be implemented to restore ecosystem structure and function. Resource managers are hindered by critical research gaps regarding the linkages between, as well as the effects of different restoration actions on, above‐ and belowground ecological and hydrological properties. In the western US, we examined how two road reclamation methods (recontouring and abandonment) affect ecosystem properties relative to “never‐roaded” areas. Recontoured and abandoned sites displayed similar aboveground properties but exhibited notable differences in below‐ground properties, including soil hydraulic conductivity, organic matter, total carbon, and total nitrogen, among others. Our findings suggest that recontouring can dramatically accelerate recovery of above‐ and belowground properties so they resemble never‐roaded reference conditions. In contrast, abandoning roads generates above‐ and belowground properties that follow a different path to recovery.

Singular and interactive effects of blowdown, salvage logging, and wildfire in sub-boreal pine systems

The role of disturbance in structuring vegetation is widely recognized; however, we are only beginning to understand the effects of multiple interacting disturbances on ecosystem recovery and development. Of particular interest is the impact of post-disturbance management interventions, particularly in light of the global controversy surrounding the effects of salvage logging on forest ecosystem recovery. Studies of salvage logging impacts have focused on the effects of post-disturbance salvage logging within the context of a single natural disturbance event. There have been no formal evaluations of how these effects may differ when followed in short sequence by a second, high severity natural disturbance. To evaluate the impact of this management practice within the context of multiple disturbances, we examined the structural and woody plant community responses of sub-boreal Pinus banksiana systems to a rapid sequence of disturbances. Specifically, we compared responses to Blowdown (B), Fire (F), Blowdown–Fire, and Blowdown–Salvage–Fire (BSF) and compared these to undisturbed control (C) stands. Comparisons between BF and BSF indicated that the primary effect of salvage logging was a decrease in the abundance of structural legacies, such as downed woody debris and snags. Both of these compound disturbance sequences (BF and BSF), resulted in similar woody plant communities, largely dominated by Populus tremuloides; however, there was greater homogeneity in community composition in salvage logged areas. Areas experiencing solely fire (F stands) were dominated by P. banksiana regeneration, and blowdown areas (B stands) were largely characterized by regeneration from shade tolerant conifer species. Our results suggest that salvage logging impacts on woody plant communities are diminished when followed by a second high severity disturbance; however, impacts on structural legacies persist. Provisions for the retention of snags, downed logs, and surviving trees as part of salvage logging operations will minimize these structural impacts and may allow for greater ecosystem recovery following these disturbance combinations.

The legacy of forest management in tropical forests: analysis of its long-term influence with ecosystem models

Forest management can modify key ecosystem attributes, affecting tree growth long after the end of forest management. Long-term influence of current management on forest recovery has been explored with the FORECAST model in Pinus caribaea Morelet plantations in western Cuba. Management for three different products was simulated: biomass, fibre and timber, with differences in rotation length and harvest intensity. Our results show that biomass production can produce ecosystem degradation that may need centuries to recover. If fibre is the objective of management, ecosystem recovery would be faster than managing for bioenergy. However, only if timber is the final objective the ecosystem might be able to keep similar conditions to the natural forest. In conclusion, our results show that forest management legacies can be a key factor in accelerating of delaying forest ecosystem recovery, depending on the exploitation intensity. These results also show the utility of ecosystem-level management models to analyze alternative management scenarios and their effects on the forest ecosystem.

Do fungi have a role as soil stabilizers and remediators after forest fire?

The functional roles of fungi in recovery of forest ecosystems after fire remain poorly documented. We observed macrofungi soon after fire at two widely separated sites, one in the Pacific Northwest United States and the other in southeastern mainland Australia. The range of species on-site was compared against macrofungi reported after the volcanic eruption at Mount St. Helens, also in the Pacific Northwest. Each of the three sites shared species, particularly representatives of the genus Anthracobia. Soon after disturbance, we noted extensive mycelial mats and masses of fruit-bodies of this genus, particularly at heavily impacted microsites. The mycelial mats appeared to play an important functional role on-site, possibly aggregating soil particles in otherwise highly erodable landscapes. We hypothesise that fungi such as Anthracobia are pivotal species in early system recovery after disturbance, helping minimize the movement of soil in the absence of plant roots. As plant root systems recover, the importance of these fungi in soil stabilization may diminish. Other functional roles of early postfire fungi might include nutrient acquisition, leading to the reestablishment of vegetation. These potential roles need to be experimentally tested and relevant findings incorporated into programs aimed at restoring forest ecosystems after disturbance.

The Use of Arthropods as Indicators of Ecosystem Integrity in Forest Management

Abstract Arthropods play vital roles in various ecosystem functions and respond acutely to habitat manipulation. Diversity and community dynamics of arthropods are strongly correlated with ecosystem functioning. Arthropod community structure reflects habitat heterogeneity, as well as development and recovery of forest ecosystems after natural and anthropogenic disturbances. Arthropod community structure also reflects the degree of fragmentation and isolation of forest ecosystems on the landscape. Arthropods are good indicators of the overall biodiversity and ecosystem integrity of forests and can be used for evaluating and designing sound ecosystem management plans.

Forest ecosystem recovery in the southeast US: soil ecology as an essential component of ecosystem management

The forestry industry in the southeastern United States relies upon soils that are highly eroded and depleted of their original organic matter and nutrient content. Pro-active land management can ensure continued and possibly increased production and revenue through the management and recovery of the soil resource. With an emphasis on loblolly pine ( Pinus taeda L.) forests, this review integrates land-use history, pine ecology, silviculture, soil ecological research and the implications for forest management into a single discussion. Promoting soil recovery involves knowledge of ecosystem history and disturbance as well as nutrient cycling mechanisms, pools, fluxes and soil forming factors. Research on the rhizosphere is an area that is needed. Recovery of regional soils may confer benefits of drought and disease resistance. The goal of sustainable forestry is compatible with soil recovery; however, the technology and practices of modern forestry deserve thorough evaluation. Emphasis on the continued production of commodities, the agricultural model, is much different from managing for the functioning of healthy forest ecosystems. Many of the practices and outcomes of intensive forest management, including short rotations, harrowing, subsoiling, and burning or removal of logging slash, seem to be at odds with the goal of soil recovery. Best management practices that foster soil recovery include less intensive stand utilization and reduced soil disturbance. Stem-only harvest and longer rotations permit a recovery of soil biodiversity and an accrual of detritus and soil organic matter. Windrowing and similar techniques have dramatic and lasting effects on soil development. No-tillage agriculture as a model for pine plantations is discussed.