Heavy Logging Research Articles

Vegetation structure influences the vertical stratification of open- and edge-space aerial-foraging bats in harvested forests

Heavy logging leads to regrowth of dense forest, which may adversely affect the flight and foraging activities of bats. We compared insectivorous bat activity and insect abundance at three heights (understorey, subcanopy and canopy), two locations (forest and track) and three time periods (evening, night and dawn), in old and young regrowth sites in south-eastern Australia (456 detector-hours). We measured activity levels of all bats and four echolocation guilds—one open-space and three edge-space aerial-foraging guilds. Mean bat activity in the subcanopy and canopy was up to 11 times that in the understorey of forests, a pattern opposite to that of insect abundance. However, bat activity in the two upper strata was lower in young regrowth than in old regrowth. Vegetation was more cluttered in young regrowth at these upper heights (closer stems and less vertical space in the subcanopy). Mean activity on the track was 2–5 times higher than in the forest, particularly at understorey level (17 times higher for all bats), where vegetation was less cluttered (more distant understorey trees and shrubs, and less cover of ground vegetation). Time of night had little effect on bat activity. The negative response of bat guilds to increased clutter was strongest in the open-space guild and weakest in the edge-space guild with the highest frequency calls. There was an interaction between insect abundance and an index of vegetation openness, with high values of both variables producing high bat activity levels for all bats and the two highest frequency call guilds. Our results highlight the need for management practices in logged forests that increase or preserve the amount of flight and foraging space available to bats.

Compaction of forest soils with heavy logging machinery affects soil bacterial community structure

Soil compaction is widespread but tends to be most prevalent where heavy machinery is used in landfill sites, agriculture and forestry. Three forest sites strongly disturbed by heavy logging machinery were chosen to test the physical effects of different levels of compaction on soil bacterial community structure and soil functions. Community analysis comprised microbial biomass C and T-RFLP genetic profiling. Machine passes, irrespective of the compaction level, considerably modified soil structural characteristics at two soil depths (5–10 cm; 15–20 cm). Total porosity decreased up to 17% in the severe compaction. Reflected in this overall decline were large decreases in macroporosity (>50 μm). Reduction in macroporosity was associated with higher water retention and restricted gas exchange in compacted soils. The strongest effect was observed in the severely compacted wheel tracks where air and water conductivities were reduced permanently to 10% or even lower of the original conductivities of undisturbed soils. Very slow drainage in combination with a dramatically reduced gas permeability led to unfavorable soil conditions in severely disturbed traffic lanes reflecting the changes in the total bacterial community structures at both soil depths. Additionally, microbial biomass C tended to be lower in compacted soil. Our results indicate that the type of severe treatments imposed at these forest sites may have strong adverse effects on long-term soil sustainability.

Riparian influences on carbon isotopic composition of tree rings in the Slave River Delta, Northwest Territories, Canada

Tree-ring cores from two white spruce ( Picea glauca) trees at each of three sites within the Slave River Delta, Northwest Territories, Canada, were separated, processed for α-cellulose and analyzed for their carbon isotope composition. The three carbon isotope ( δ 13C cellulose) time series, collectively covering the time period from 1689 to 2003, were statistically correlated with average Historical Monthly Climate Grid temperature and precipitation for the period 1901–2000. The results suggest that the trees from all three sites show a distinct trend towards more enriched δ 13C cellulose values with time, implying more stressful environmental conditions possibly related to the overall 20th Century drying of the Slave River Delta. Anthropogenic impacts of heavy logging and the construction of a large upstream dam may also be present in the δ 13C cellulose time series. The main focus of the study relates to the different nature of the three riparian sites. The δ 13C cellulose values of the trees from the two sites ≥ 50 m from the river at higher elevation suggest a relationship with moisture-deficit-stress (MDS) emanating from hydroclimate effects during the non-growing and growing seasons. The δ 13C cellulose values from a site adjacent to the river at lower elevation, however, suggest that these same effects can manifest as moisture-excess-stress (MES) on the trees. The relationships between these two types of moisture stress and the δ 13C cellulose values of the trees from the sites with obvious riparian differences are discussed in detail.

Postlogging structural changes and regeneration of Olea welwitschii (Knobl) Gilg. & Schellemb. in the Kibale National Park, Uganda

AbstractThe study was conducted in the Kibale National Park forest where both light and heavy logging was conducted during 1969–1970. The forest areas which had high stocking densities of Olea suffered the heaviest logging impacts. Research on the autecology of Olea welwitschii (Knobl) Gilg. & Schellemb., an excellent timber species, was undertaken to examine the effects of differential logging intensities on its residual population structure, tree morphology and regeneration. A series of quadrats were placed in the lightly and heavily logged forests, unlogged mature forest and in ecotonal forest tracts. All Olea trees, irrespective of size within the plots, were identified, marked, mapped and their diameter at breast height, height, branching height and multiple stemming measured. Results indicate that the distribution and abundance of Olea tree species was influenced by variations in human disturbances. Heavy forest disturbances created conditions similar to those in ecotonal sites which encouraged successful Olea tree colonization, regeneration and fast growth. However, the closed and semi‐closed canopy conditions following logging suppressed Olea regeneration. These observations qualify Olea to be a colonizer and light demander in the juvenile seral stages. It exhibits high tree mortality across all size classes and low survival under natural forest conditions compared with other typical forest climax species. Heavy logging also led to shorter multiple stemmed Olea trees which retained multiple branches on the trunks below the main canopy. Consequently, low‐level timber harvesting seems compatible with sustainable Olea utilization. The characteristics of Olea as a colonizing as well as canopy tree species makes it ideal for domestication, forest restoration and plantation management.

Effects of forest structure and composition on food availability for Varecia variegata at Ranomafana National Park, Madagascar

We present a summary of a long-term field study that examined the effects of forest disturbance on the availability of palatable fruit and its utilization by V. variegata. Forest structure and tree species composition were measured in three adjacent study areas, with different histories of disturbance, in Ranomafana National Park (RNP), Madagascar. V. variegata abundance was monitored by frequent encounters with resident groups and periodic censuses conducted along trails. Finally, the abundance of mature fruit in species used by V. variegata was scored monthly at representative trees at several locations. V. variegata abundance was most consistent in the least anthropogenically disturbed site, while no established lemur groups were observed in the heavily logged site for over a decade post-harvest. Lemur abundance was variable in the selectively logged site. The presence of select food trees, particularly specimens with voluminous crowns capable of producing abundant fruit crops, appears to be key to the establishment and expansion of V. variegata groups. Our analysis of year-long fruit utilization revealed a high degree of preference for several species of trees. Two species exhibited mature fruit in a low percentage of stems but were available for a protracted period of time, while two additional species showed high intraspecific fruiting synchrony and were available for a shorter period of time. These contrasting phenologies, rather than the individual tree species, may be most important to V. variegata due to their coincident timing of fruit maturation with key lemur life-history events. Any disturbance-natural or anthropogenic-that disrupts the phenology cycles of food trees has the potential to impact lemur abundance and dispersion. Intense disturbances, such as heavy logging or severe cyclones, have long-lasting impacts on fruit production, while selective logging or moderate cyclonic windthrow cause more transient impacts. V. variegata is adapted to deal with an intrinsically erratic food supply by virtue of its reproductive biology and social behavior.

Wet-Weather Timber Harvesting and Site Preparation Effects on Coastal Plain Sites: A Review

Abstract Increased interest in sustainable forestry has intensified the need for information on the interactions of forest soils, harvesting methods, site disturbances, and the efficacy of methods for ameliorating disturbances. On wet pine flats, such as those commonly found in the Atlantic and Gulf Coastal Plains, conditions such as frequent rainfall, low relief, and poor internal soil drainage often predispose forest soils to harvest disturbances and potential damage. Typical forest operations use heavy logging equipment, such as rubber-tired feller-bunchers and skidders. During dry soil conditions, these machines cause little soil disturbance, but under moist to saturated conditions, such operations may compact soils and interfere with normal soil drainage. Many studies have been conducted to characterize soil disturbance and site preparation effects on tree seedling survival and growth and to evaluate the amelioration effect of site preparation on disturbed soils. However, results are sometimes contradictory due to site specificity, and results have not been summarized in the context of pine plantation management. This article summarizes previous research results of the wet-weather harvesting and bedding effects on soil properties as related to loblolly pine (Pinus taeda) productivity for a variety of Coastal Plain region sites types. South. J. Appl. For. 28(3):137–151.

Stand history and its consequences for the present and future dynamic in two silver fir (Abies alba Mill.) stands in the high Pesio Valley (Piedmont, Italy)

Two silver fir (Abies alba Mill.) forest stands have been identified on unmanaged parts of previously managed forests in the Alta Valle Pesio e Tanaro Regional Park (Piedmont, Italy) in order to study their origin, past forest dynamic and disturbance history. The historical development and the successional history of these stands were investigated in two plots of 2000 m$^2$ by means of the following techniques: size and age structure analysis, abrupt growth changes analysis, establishment of pioneer species and of early-seral shade-intolerant species, historical data of logging. The stands investigated are relatively young; in the past 70 years some periods of heavy logging have been identified. Intense cutting has caused the establishment of an abundant regeneration of shade intolerant early-seral broadleaves species. The peak recruitment period of the broadleaves occurred around 1940 in plot 1 and around 1975 in plot 2. The current structures and composition of the forest are therefore the result of anthropogenic activity, indeed, the presence of pure silver fir stands in the past were the result of human intervention. The silver fir will share future dominance with several broadleaves species such as the beech (Fagus sylvatica L.) and the sycamore (Acer pseudoplatanus L.) although the exact successional status of these stands is unresolved.

Literary Imaginings of the Bunya

By the time that Europeans became acquainted with the bunya, the gum tree was already well established as the iconic Australian tree. The genus Eucalyptus, with all its locally specific variants, was both distinctive to the continent and widely dispersed throughout it. In contrast, the bunya tree (classified as Araucaria bidwillii in 1843) grew in a small area of what is now South-East Queensland and was seen by few Europeans before the 1840s, when Moreton Bay was opened to free settlement. The physical distinctiveness of the bunya tree, and stories of the large gatherings which accompanied the triennial harvesting of its nut, aroused the curiosity of early European explorers and settlers, and in the late nineteenth and early twentieth centuries the bunya tree achieved a special status in local civic culture. Although heavy logging had largely destroyed the great bunya forests, the tree was planted extensively in school grounds, around war memorials and in long avenues in parks.

RAPD Marker Diversity Within and Among Natural Populations of the Clonal Tree Cryptomeria japonica D. Don.

The Japanese cedar, Cryptomeria japonica D. Don., is one of the most important endemic species in Japan. A long history of heavy logging has resulted in natural populations being discontinuously distributed and scattered among small, restricted areas. An understanding of the patterns of genetic variability among and within populations of C. japonica is important for conserving the genetic resources of this economically important species. We studied genetic variation by random amplified polymorphic DNA (RAPD) markers in C. japonica of Kyoto prefecture, western Japan. A total of 398 plants sampled from six natural populations were analyzed by ten arbitrarily chosen decamer primers, resulting in 50 highly reproducible RAPD bands. Analysis of molecular variance partitionated the RAPD variation into the among- and within population components. The within-population component accounted for 93.75% of the variation. The among-population component accounted for only 6.25%. Indirect estimates of gene flow indicated that the average number of migrants exchanged among six populations per generation was 3.72. A Mantel test for each population did not yield significant correlations between geographic and genetic distances. The extent and distribution of C. japonica diversity in the Kyoto prefecture is in agreement with the conclusion that long-lived, wind-pollinated, out-crossing species with wide ranges retain a considerable amount of genetic diversity within populations and exhibit little genetic differentiation among populations.

The effects of logging and grazing on the insect community associated with a semi-arid chaco forest in central Argentina

The ground-dwelling insect community associated with semi-arid chaco forest in the Chancanı́ Natural Park and Forest Reserve (Córdoba, central Argentina) was studied from pitfall trap collections. The taxonomic composition and functional structure of the community present in the natural climax forest was compared with that of a degraded forest (shrubland) resulting from heavy logging and grazing. The studied communities differed significantly in taxonomic composition, sharing less than half of the insect families and less than a third of the Coleoptera species. The shift in dominant families within the Coleoptera reflected the habitat changes imposed by disturbance, mainly the scarcity of litter and presence of cattle dung in the shrubland. Such effects were also reflected in changes in the relative size of insect feeding guilds within the two habitats, scavengers being remarkably under-represented in the shrubland. Given the key role of scavenging insects as decomposers in arid systems, this observation could have profound implications for the functioning of this habitat type.

Elephants, selective logging and forest regeneration in the Kibale Forest, Uganda

ABSTRACTThe Kibale Forest, western Uganda, is the only site where studies have compared the impact of elephants on rainforest regeneration in logged and unlogged control areas. Elephants used heavily logged areas more than lightly logged and unlogged areas. Forest gaps were used more by elephants than closed-canopy areas and large gaps more than small ones. Gaps were larger in logged than unlogged forest. There were lower densities of young trees (saplings and poles) and a higher incidence of elephant damage to them in heavily logged forest than in lightly logged and unlogged sites. Elephant use of an area and damage to young trees was inversely or unrelated to the density of young trees and directly related to the density of herbaceous tangle. Heavy logging resulted in large areas of herbaceous tangle, which attracted elephants who suppressed forest regeneration by damaging young trees and perpetuating the herbaceous tangle. The tangle directly competed with regeneration of young trees while also attracting elephants and rodents (seed and seedling predators) and facilitating increased windthrow of trees. Selective browsing of young trees by elephants affected rates of regeneration, growth form and species composition. Rather than remove elephants, a more effective and humane approach to long-term management of logging is to reduce logging offtake and incidental damage caused by timber extraction.

Northern Flying Squirrel Densities in Fir Forests of Northeastern California

The northern flying squirrel (Glaucomys sabrinus) is the primary prey of northern spotted owls (Strix occidentalis caurina) and California spotted owls (S. o. occidentalis) throughout much of the owls' ranges. Flying squirrel abundance patterns, however, are poorly documented. Using capture-recapture techniques to estimate density, we compared flying squirrel densities among 3 types of fir (Abies spp.) forests in Lassen National Forest, northeastern California. We compared densities between 3 each of old and shelterwood-logged fir stands in 1990 and among 4 each of old, shelterwood, and young fir stands in 1991-92. Shelterwood stands had been logged and had undergone site preparation 5 years prior to our study. In 1990 flying squirrel density was greater in old (? = 2.76 squirrels/ha, SE = 0.55) than in shelterwood (? = 0.31 squirrels/ha, SE = 0.11) stands (P = 0.005). In 1991-92 density varied (P = 0.001) among the 3 stand types, averaging 3.29 squirrels/ha (SE = 0.63) in old, 2.28 squirrels/ha (SE = 0.18) in young, and 0.37 squirrels/ ha (SE = 0.17) in shelterwood stands. Body mass of adult males and females and recapture rate did not differ (M, P = 0.438; F, P = 0.983; P = 0.218, respectively) between old and young stands, and percent juveniles captured was greater (P = 0.052) in old than in young stands. Diet analyses were consistent with other studies and indicated that sporocarps of hypogeous fungi were a common food source. Frequency of hypogeous sporocarps was correlated (r s = 0.860, P < 0.001) with flying squirrel density, but cavity density and understory cover were not (P = 0.344 and 0.217, respectively). Flying squirrels were not old-growth specialists; however, low densities in shelterwood stands suggest that heavy logging and intensive site preparation negatively affected flying squirrel populations.

Preliminary Survey of Relative Group Density of Macaca fuscata yakui in Relation to Logging History at Seven Sites in Yakushima, Japan

The forest habitat of the Yakushima macaque varies in quality as a result of logging, secondary growth and conifer plantations. A preliminary survey was made of macaque populations at 7 sites representing a range of habitat quality. All sites were located at between 300 and 800m asl, in the warm temperate broad-leaved forest zone in northwest Yakushima (30°N, 131°E), Japan. The extent of logging within a 1km2 plot at each site was assessed using image analysis of forestry maps. The proportion of the plot which had been logged within the previous 25 years ranged from 0 to about 68%, within 50 years from 0 to 79%, and within 75 years from 28 to 79%. Observations, vocalisations and droppings of macaques were recorded for a total of 284hr along census trails of between 2.2 and 3.5km. This included four ‘full’ days (7.5-8.5hr) for each site, which were used for the analyses. Macaques were found at all sites. The mean number of groups seen or heard ranged from 0.11 to 0.82/km/day, and was positively correlated (rs=0.64) with the proportion of mature forest at each site. There was no clear correlation between the mean detection rate of groups and the rate at which droppings were found. The latter may be a less accurate measure of relative group density in a short-term survey. Although Yakushima macaques do utilise areas within 25 years of heavy logging, more groups were found in areas where logging was less recent and/or less extensive. A long-term survey is now underway which will assess the details of this relationship, the influence of forestry plantations, and seasonal variation in use of different habitat types.

The role of mycorrhizas in the regeneration of some Malaysian forest trees

An investigation was made into the availability of mycorrhizal inoculum and the response of tree seedlings to mycorrhizal infection in West Malaysian forests. Spores of vesicular arbuscular (VA) mycorrhizal fungi in the soil were reduced by 25% after selective logging and by 75% after heavy logging, VA infection in the roots of plants persisting on, or colonizing, a heavily logged site was reduced by up to 75% . The most probable number (MPN) of VA propagules in sieved soil was up to ten times greater than spore density, but was also greatly reduced by heavy logging. This resulted in reduced infectivity of soil from the heavily logged site, as demonstrated by reduced VA infection of bioassay plants. The infectivity of soil declined following sun drying, but sun-dried soil devoid of vegetation retained some infectivity even after 12 months storage. Overall the data suggest that root and hyphal fragments are more important than spores as inoculum in disturbed forest, and that in undisturbed forest living roots and hyphae are likely to be important sources of infection. In a pot experiment, shoot growth of two test species, Albizia falcataria (L.) Becker and Parkia speciosa Hassk. responded more to VA mycorrhizal infection than to P fertilization over the range 0-6 g triple superphosphate per 8 kg of soil. The response to inoculation with a cocktail of ‘introduced’ VA fungi propagated in pot cultures was greater than the response to inoculation with ‘indigenous’ fungi propagated in pot cultures from roots and soil collected in undisturbed forests. Another test species, Intsia palembanica Miq., also responded better to mycorrhizal infection than to P fertilization, and better to VA mycorrhizal infection than to ectomycorrhizal infection. Intsia palembanica seedlings growing around mature dipterocarps quickly became ectomycorrhizal, suggesting that at least some ectomycorrhizal fungi infect both dipterocarps and Intsia. Shorea leprosula Miq. seedlings growing naturally in the forest had ectomycorrhizas 20 days after germination, i.e. before they had true leaves, and within 7 months supported up to 11 different ectomycorrhizal fungi. However, seedlings isolated from contact with the roots of mature Shorea trees remained uninfected in the held for up to 6 months. This shows the importance of contact with living ectomycorrhizal roots for early infection of dipterocarp seedlings, a point which should be recognized in logging operations and forest regeneration programmes.

Post-logging tree mortality and major branch losses in Kibale Forest, Uganda

This study was undertaken to establish whether selective felling and the existence of large forest gaps influence the dynamics of tree and branch falls. Censuses of fallen trees and large branch falls in uncut, lightly cut and heavily cut forest tracts were conducted for 20 months. Dead-standing trees in the study compartments were enumerated only three times at 6-month intervals. In lightly cut forest, the densities of live and dead tree and branch falls were similar but monthly tree snaps were more than uproots. However, for heavily cut forest, total tree falls (snap + uproot) involved more live than dead trees. There were more live than dead tree snaps and the rate of tree uproots was low. in contrast to the above, the density of tree snaps and uproots in uncut mature forest was similar. For total tree falls and live tree or large branch falls, the heavily selectively cut forest exhibited higher rates than uncut and lightly cut forest tracts. The annual rates of live tree falls ha −1 were 1.30 for lightly cut, 3.30 for heavily cut and 1.74 for uncut mature forest. It appears that heavy logging increases tree mortality rates through falls where more live tree snaps than uproots are involved.

Age Structure and the Maintenance of Pinus pungens in Pine-oak Forests of Southwestern Virginia

-The age structure of table mountain pine Pinus pungens Lambert was examined in three pine-oak forests in southwestern Virginia. The age distribution of P. pungens was bimodal with a major peak in the large tree age classes and a smaller secondary peak in the seedling age classes. The predominance of advanced regeneration of oaks and other gap-exploiting woody species, and the underrepresentation of P. pungens seedlings and small trees, indicates that maintenance of P. pungens in these forests is unlikely under current disturbance regimes. It is hypothesized that the P. pungens populations studied originated from seed trees left on the sites following heavy logging and fires at the turn of the century.

Impact of logging equipment on water infiltration capacity at Olmotonyi, Tanzania

Assessment and comparison of the influence of compaction caused by two types of logging equipment, a farm tractor and a manually pulled sulky, on water infiltration capacity was made in two Cupressus lusitanica compartments, under wet conditions. There were significant increases in soil bulk density for wheel-rutted and log-compacted sites during tractor extraction, with very small changes in density for the sulky-logged areas. Water infiltration rates were more significantly reduced in the tractor than the sulky-harvested areas, with more reduced rates in the wheel ruts than log-compacted sites. Infiltration rates decreased compared to increased bulk density, suggesting increased erosion potential with the degree of compaction. There was a significant positive correlation between infiltration rate and litter depth, with higher rates for the light (sulky) than for the heavy (tractor) logging equipment. The results suggest that the use of heavy logging equipment, especially on soils with low bearing strength, increases soil compaction and may lead to increased erosion potential.

Floristic composition and structure of a rainforest area 25yr after logging

AbstractIn 1949 an area of undisturbed warm temperate rainforest (simple notophyll vine forest) in mid‐north coastal New South Wales, Australia was studied in terms of both floristics and structure (Burges A. &amp; Johnston R. D. J. Ecol. 41, 72‐83, 1953).During 1955‐56, the area in which the transect was located was logged. Over 90% of the upper closed canopy trees adjacent to the creek and on the lower slope and about 35% of canopy trees on the upper slope were removed.The area was reassessed in terms of floristics and structure in 1981. The greatest impact of logging in the study area was structural and largely confined to the flat adjacent to the creek and to the lower slope. With the exception of the remaining gaps covering 6% of the area, structural recovery time is estimated at 140‐190 yr. In the gaps structural recovery may take up to 250 yr.All flowering plants, ferns and mosses previously recorded were present 25 yr after logging. The two alien plant species on the site are short lived intolerant species and gradually disappearing with canopy closure of the regenerating forest.The regeneration of the original tree species is healthy and vigorous with most regeneration resulting from the growth of advance regeneration present at the time of logging or the germination of new seedlings. Eleven per cent of the regeneration is attributable to coppicing. The importance of remnant canopy trees as a source of propagules for the trees and epiphytes is recognised. The larger openings are slower to recover as a result of lack of protection from frost. The stability of floristic composition of this area of warm temperate rainforest following heavy logging is demonstrated.

Kentucky's Hardwood Resource

Abstract Old-growth forests that once covered the state almost entirely were destroyed by land clearing that began in the mid-eighteenth century and by heavy logging after the Civil War. Strip-mining after World War II damaged many sites. With the decline in harvesting intensity and the increase of sound strip mine reclamation, the forests are slowly yet steadily recovering. Today forests occupy about half of the land area in the state, the distribution being concentrated in the mountainous eastern portion. Hardwoods dominate overwhelmingly among many species growing on a diversity of sites. Oaks and hickories are the most important timber species. They are discriminated against by partial cutting--essentially high-grading--that favors development of shade-tolerant species like American beech and sugar maple. Volume growth is good, with growing stock accruing 2.5 times as fast as it is being removed. Improved management and utilization would markedly increase the hardwood resource and the volume and quality of timber that could be drawn from it.

THE NEED TO STUDY SILVICULTURAL EFFECTS OF MECHANIZED LOGGING SYSTEMS IN EASTERN CANADA

Biological problems which may result from the use of heavy logging equipment are discussed. Scarification from logging rarely produces enough seedbed favourable to natural regeneration. Full-tree logging may cause nutrition problems by removing tree crowns from poor sites. Well designed studies of various kinds of logging systems are needed to assess their effects on the stand, soil and future regeneration. Studies of nutrient cycling in native forest stands might indicate some of the effects of full tree logging.