Mature Conifer Research Articles

Where do conifers regenerate after selective harvest?: A case study from a New Zealand conifer–angiosperm forest

Ensuring the regeneration of selectively harvested canopy tree species remains challenging in mixed forests where species have different requirements for successful recruitment. Mature conifer trees (Podocarpaceae) have been selectively harvested from parts of New Zealand's North Island conifer–angiosperm forests. Forest managers require guidance on podocarp restoration, given current dominance by the shade-tolerant angiosperm Beilschmiedia tawa. We surveyed seedling densities of podocarps and B. tawa ca. 40 years after harvesting and found that B. tawa seedlings outnumbered the combined total of podocarp seedlings by approximately 3:1. There were significant, positive associations between seedlings of most species suggesting that safe sites for establishment were similar, in part, for the suite of study species. These sites are the same as those where adult podocarp trees are reported to occur. We developed and tested candidate models predicting the influence of environmental factors on seedling regeneration; these focused on the roles of soil nutrients, landform, canopy openness, tree fern cover, ground cover by ferns and disturbance. We found the most support for models that used a combination of soil nutrients, canopy composition, landform index and disturbance type to predict seedling occurrence. A positive relationship was found between soil nitrogen (N) and seedling occurrence of all species surveyed, and this relationship alone had most support in explaining the occurrence of Prumnopitys taxifolia and Dacrycarpus dacrydioides seedlings. We found little difference in the current sites of young Prumnopitys ferruginea and B. tawa; both species occur in dense stands of adult B. tawa, although in contrast to B tawa, P. ferruginea seedling occurrence declined with increasing soil phosphorus (P). Dacrydium cupressinum also declined with increasing soil P. Given that the studied forest fits the apparent global trend for angiosperm ascendancy we suggest that manipulations will be required to restore podocarps. Possible interventions are planting seedlings and/or removing some of the B. tawa canopy. Given that podocarp seedlings were found on soils with low soil P, but high soil N concentrations, soil nutrient status should be taken into account during management.

Habitat Selection in a Changing Environment: The Relationship Between Habitat Alteration and Spotted Owl Territory Occupancy and Breeding Dispersal

Abstract Abstract. Understanding the effect of habitat alteration on avian behavior is important for understanding a species' ecology and ensuring its conservation. Therefore, we examined the relationship between Spotted Owl habitat selection and variation in habitat in the Sierra Nevada. We estimated habitat selection by modeling the probability of territory colonization (γ), territory extinction (ε), and breeding dispersal in relation to the amount of mature conifer forest within and among territories. Alteration of ≥20 ha of mature conifer forest (coniferous forest with >70% canopy cover dominated by medium [30.4–60.9 cm dbh] and large [>60.9 cm dbh] trees) within individual territories (n = 66) was negatively related to territory colonization and positively related to breeding dispersal probability. Although territory extinction was negatively related to the amount of mature conifer forest, it was not clear whether this relationship was due to variation of mature conifer forest within or among territories. Although modeling results for territory colonization and extinction generally supported the hypothesis that individuals are “ideal” when selecting a habitat in the sense that they settle in the highest-quality site available, we did not find a clear benefit in terms of habitat quality for Spotted Owls that exhibited breeding dispersal.

Status of the Hen Harrier Circus cyaneus in the UK and Isle of Man in 2004, and a comparison with the 1988/89 and 1998 surveys

Capsule The population of breeding Hen Harriers in the UK and Isle of Man increased between 1998 and 2004, although country and regional trends differed. Aims To estimate the size of the UK and Isle of Man Hen Harrier breeding population in 2004, and to compare this with previous estimates made in 1988/89 and 1998. Methods Surveys were carried out in core and a stratified random sample of 10-km squares throughout the known range, using the same methods as in the 1988/89 and 1998 national surveys. Results There were an estimated 806 territorial pairs in the UK and Isle of Man in 2004, a significant 41% increase from the 1998 estimate of 570 pairs. Increases were found throughout, with the exception of south and east Scotland and England, where numbers decreased. Scotland held 79% of the UK and Isle of Man breeding population in 2004, and 10% of Scottish pairs were associated with non-moorland habitats, such as mature conifer plantations and scrub/brash. Conclusions There was a substantial increase in the breeding population in most regions of the UK and Isle of Man between 1998 and 2004, possibly aided by increased use of non-moorland habitats. However, populations declined in upland areas of southern and eastern Scotland and northern England. Continuing illegal persecution arising from perceived conflicts between breeding Hen Harriers and driven grouse shooting may be a major cause of these regional declines.

HABITAT SELECTION IN A CHANGING ENVIRONMENT: THE RELATIONSHIP BETWEEN HABITAT ALTERATION AND SPOTTED OWL TERRITORY OCCUPANCY AND BREEDING DISPERSAL

Abstract Abstract. Understanding the effect of habitat alteration on avian behavior is important for understanding a species' ecology and ensuring its conservation. Therefore, we examined the relationship between Spotted Owl habitat selection and variation in habitat in the Sierra Nevada. We estimated habitat selection by modeling the probability of territory colonization (γ), territory extinction (ϵ), and breeding dispersal in relation to the amount of mature conifer forest within and among territories. Alteration of ≥20 ha of mature conifer forest (coniferous forest with >70% canopy cover dominated by medium [30.4–60.9 cm dbh] and large [>60.9 cm dbh] trees) within individual territories (n = 66) was negatively related to territory colonization and positively related to breeding dispersal probability. Although territory extinction was negatively related to the amount of mature conifer forest, it was not clear whether this relationship was due to variation of mature conifer forest within or among terri...

Watershed Nitrogen and Mercury Geochemical Fluxes Integrate Landscape Factors in Long-term Research Watersheds at Acadia National Park, Maine, USA

This paper is an overview of this special issue devoted to watershed research in Acadia National Park (Acadia NP). The papers address components of an integrated research program on two upland watersheds at Acadia NP, USA (44 degrees 20' N latitude; 68 degrees 15' E longitude). These watersheds were instrumented in 1998 to provide a long-term foundation for regional ecological and watershed research. The research was initiated as part of EPA/NPS PRIMENet (Park Research and Intensive Monitoring of Ecosystems Network), a system of UV-monitoring stations and long-term watershed research sites located in US national parks. The initial goals at Acadia NP were to address research questions about mercury, acid rain, and nitrogen saturation developed from prior research. The project design was based on natural differences in forests and soils induced by an intense wildfire in one watershed in 1947. There is no evidence of fire in the reference watershed for several hundred years. We are testing hypotheses about controls on surface water chemistry, and bioavailability of contaminants in the contrasting watersheds. The unburned 47-ha Hadlock Brook watershed is 70% spruce-fir mature conifer forest. In contrast, burned 32-ha Cadillac Brook watershed, 4 km northeast of the Hadlock watershed, is 20% regenerating mixed northern hardwoods and 60% shrub/rocky balds. Differences in atmospheric deposition are controlled primarily by forest stand composition and age. The watersheds are gauged and have water chemistry stations at 122 m (Cadillac) and 137 m (Hadlock); watershed maximum elevations are 468 and 380 m, respectively. The stream water chemistry patterns reflect, in part, the legacy of the intense fire, which, in turn, controls differences in forest vegetation and soil characteristics. These factors result in higher nitrogen and mercury flux from the unburned watershed, reflecting differences in atmospheric deposition, contrasting ecosystem pools of nitrogen and mercury, and inferred differences in internal cycling and bioavailabilty.

Effects of bark beetle outbreaks on avian biodiversity in the British Columbia interior: Implications for critical habitat management

The health of coniferous and mixed forests in western Canada is a critical forest management issue with implications for the forest industry, biodiversity conservation, and regional land use planning. The mixed forests of interior British Columbia have high biodiversity and species abundance, and support rich communities of over 185 wildlife vertebrate species, about 24% of which are cavity-nesters. These cavity-nesting birds and mammals live in complex, strongly structured wildlife communities (Nest Webs) that consist of an array of excavators and consumers of tree holes, many of which have strong preferences for large, old and decayed trees, especially deciduous trees, for nesting.Mountain pine beetle (MPB; Dendroctonus ponderosae Hopkins) and fire are the two major natural disturbance types structuring mature conifer stands in the interior of the province. The temporal changes in value and availability of dead and dying trees and their associated insect fauna are expected to result in stand-level variation in wildlife populations. Our research in the Cariboo-Chilcotin region showed that insect outbreaks can initially result in improved conditions for cavity-users and many other birds that feed on insects in dead and dying trees, but as the epidemic proceeds, these enhanced conditions deteriorate for many species as the supply of forest insects and old trees decline. The cumulative effects of habitat and environmental changes on the working landscape have the potential to negatively affect the stability of wildlife populations. This paper summarizes field observations regarding changes in forest stand conditions and avian biodiversity and evaluates the patterns of habitat change, beetle salvage, and wildlife responses as the mpb epidemic runs its course. It also discusses some of the issues that forest managers face when considering the maintenance of critical habitat for cavity-nesting species.

The soil seedbank of a lowland conifer forest: The impacts of clear-fell management and implications for heathland restoration

Understanding the composition and dynamics of soil seedbanks beneath mature conifer plantations is important for managing biodiversity in rotational forestry systems and in the restoration of former communities following the removal of tree crops. We examined the role of the buried seedbank in vegetation development after clear-felling of stands within coniferous plantation forest in eastern England. The buried seedbank of 29 mature stands planted in the early to mid 20th century on lowland heathland and marginal arable was determined by germination of seeds from soil cores (30 bulked cores per stand). Seedbank density was highly variable, with a mean of 3950 (S.D. ± 2400) seeds m −2. Ninety-eight species germinated, of which 37 were present in the surface vegetation of the mature stands; these 37 species had a higher density of seeds than the 61 species absent from the surface vegetation. Of those 61 species, 21 were recorded in the surface vegetation of recently replanted stands, suggesting that the seedbank may increase the plant diversity of replanted stands following clear-felling. The seedbank of mature stands was dominated by Urtica dioica and Holcus lanatus. Comparison of seeds in the top 20 cm of soil between four paired mature and replanted stands showed felling and cultivation prior to replanting had little effect on either the density of the buried seedbank or the vertical seed density profile. Twenty-nine of the species recorded in the buried seedbank of mature stands were characteristic of heathland assemblages of the region, but were present at low densities. Notably, a number of perennial grass species characteristic of heathland were absent, while Calluna vulgaris occurred in the seedbank of few stands and then at low density. The potential for grass-heath restoration following clear-felling of first rotation conifer stands investigated in this study is likely to be low.

Defining alternative futures and projecting their effects on the spatial distribution of wildlife habitats

This study had two purposes: (1) to inform a public process that would propose land use zoning for the Chico Creek Watershed in Washington State, USA and (2) to develop and demonstrate the use of readily accessible analytical tools and data for similar public processes across Washington. Three development alternatives (Planned Trend, Moderate, and Conservation) were designed by local citizens and county planners. We created artificial landscapes that depicted how land use zoning and land management practices would effect the spatial distribution of vegetation types. Wildlife–habitat relationship models were constructed for nine focal species. Using computer software known as HABSCAPES, the spatial distributions of habitats were mapped for each species. Under all alternatives the amount of forest vegetation decreased but the amount of mature conifer forest increased relative to current conditions. The relative habitat area index was 0.75, 0.69, 0.71, and 0.71 for the current condition, Planned Trend, Moderate, and Conservation alternatives, respectively. For six species, all future alternatives resulted in less habitat than the current condition, but for three species, all future alternatives resulted in more habitat. When species status was used to weight outcomes, the moderate alternative provided slightly more conservation benefit than the conservation alternative. Lessons learned about public land use planning processes are discussed.

Status of Mature and Old‐Growth Forests in the Pacific Northwest

Nearly 10 million ha of federal lands in the Pacific Northwest have been managed under the Northwest Forest Plan since 1994. The plan reduced logging levels by 80%; only recently, however have inventories on status and condition of mature and old-growth forests become available. Our objectives were to (1) determine the areal extent of old (> 150 years) and mature (50-150 years) conifer forests based on 2000 Landsat 7 ETM+ imagery, (2) examine levels of protection, (3) determine the degree of additional protection afforded to old and mature conifer forests if late-successional reserves (LSRs) and inventoried roadless areas (IRAs) were fully protected, and (4) review management options to achieve greater protection of older forests. The historical extent of old-growth forest in the Pacific Northwest was roughly two-thirds (16,672,976 ha) of the total land area. Since the time of European settlement, approximately 72% of the original old-growth conifer forest has been lost, largely through logging and other developments. Of the remaining old growth, the Central and Southern Cascades and Klamath-Siskiyou account for nearly half Mature conifer area (4,758,596 ha) nearly equaled the amount of old conifer More than 78% of the old growth and 50% of mature forest were located on public lands. Approximately one-quarter (1,201,622 ha) of the old-growth conifer (or 7% of the historical old-growth area) was classified as GAP status 1 (strictly protected) or GAP status 2 (moderately protected). The total area of LSRs was slightly more than 3 million ha, approximately 36% (1,073,299 ha) of which contained old-growth conifer forest. Combined old and mature conifer within LSRs was approximately 59% of the total LSR area. The total amount of IRA for the Pacific Northwest was approximately 1,563,370 ha; of this, 526,912 ha (34%) was old growth. The combined area of old-growth conifer forest accounted for by protected areas (GAP 1 and 2), LSRs, and IRAs was 2,401,780 ha, which accounts for 66% of the old-growth conifer forests on public land, 51% of the old conifer in the region, and 14% of the amount that occurred historically. Outside these land designations, an additional 1,240,271 ha of old growth are on other public land and another 1,023,392 ha are on private lands throughout the Pacific Northwest. Our results indicate the need to periodically monitor status and condition of older forests and strengthen protections of old growth in the region.

Late-summer carbon fluxes from Canadian forests and peatlands along an east–west continental transect

Net ecosystem productivity (NEP) during August 2003 was measured by using eddy covariance above 17 forest and 3 peatland sites along an east–west continental-scale transect in Canada. Measured sites included recently disturbed stands, young forest stands, intermediate-aged conifer stands, mature deciduous stands, mature conifer stands, fens, and an open shrub bog. Diurnal courses of NEP showed strong coherence within the different ecosystem categories. Recently disturbed sites showed the weakest diurnal cycle; and intermediate-aged conifers, the strongest. The western treed fen had a more pronounced diurnal pattern than the eastern shrub bog or the Saskatchewan patterned fen. All but three sites were clearly afternoon C sinks. Ecosystem respiration was highest for the young fire sites. The intermediate-aged conifer sites had the highest maximum NEP (NEPmax) and gross ecosystem productivity (GEPmax), attaining rates that would be consistent with the presence of a strong terrestrial C sink in regions where these types of forest are common. These results support the idea that large-scale C cycle modeling activities would benefit from information on the age-class distribution and disturbance types within larger grid cells. Light use efficiency followed a pattern similar to that of NEPmax and GEPmax. Four of the five recently disturbed sites and all three of the peatland sites had low water use efficiencies.

SNAGS, CAVITY-NESTING BIRDS, AND SILVICULTURAL TREATMENTS IN WESTERN OREGON

We examined cavity-nesting bird use of natural snags (n = 221) and 10- to 12-year-old snags (n = 836) created by topping mature conifers in 3 silvicultural treatments (group-selection cuts, 2-story regeneration harvests, clearcuts with retained trees) and 2 snag arrangements (clustered, scattered) in 30 Douglas-fir (Pseudotsuga menziesii) stands in the Oregon Coast Range. Eight bird species nested in created snags. Open-canopy stands (2-story and clearcut treatments) had higher levels of avian nesting, species richness, and species diversity compared to closed-canopy, group-selection stands. We did not find a difference in nesting levels between clustered and scattered snags. In created snags, most active nests were in the top 25% of the bole, cavity entrances typically faced northeast, and the presence of dead branches did not alter use of snags for nesting. Topped conifers that remained alive (n = 102) were rarely used for nesting or foraging. Since the last survey 6 years prior to our survey, the number of cavities per created snag per silvicultural treatment increased 3.3- to 6-fold, and we observed 4 additional avian species nesting; 3 were secondary cavity nesters. Total cavities per snag averaged 5.1, 4.3, and 2.5 for created snags, natural snags >12 years old, and natural snags <12 years old, respectively. Only 1 created snag fell in the decade since topping. Natural new snag recruitment resulting from residual green tree mortality was highest in 2-story stands (0.76 snag/ha) and lowest in clearcuts (0.20 snag/ha). Snags created by topping large conifers provided nesting and foraging structures for cavity-nesting birds under a range of silvicultural conditions, and use was influenced more by residual green tree density than snag arrangement. In addition, created snags increased in value for birds through their first decade (88% had cavities). Because snags created by topping last long and are readily used by birds, they should be considered a management option to improve avian habitat in managed forests.

A soil seed bank in a mature conifer plantation and establishment of seedlings after clear-cutting in southwest Japan

Compositions and spatial distribution patterns of buried viable seeds, and demographic transition from buried viable seeds to seedlings after clear-cutting were examined in a 75-year-old conifer plantation in southwest Japan. A part of the plantation was cleared in December 1997 and study plots were set up on a cleared site and a preserved site. Soil samples (a total of 105l for the preserved plot and 90l for the cleared plot) were collected from surface soils in spring 1998 and were incubated in a greenhouse for 120 days. There were an estimated 1064 buried viable seeds per square meter from 67 species in the preserved plot and 1754 seeds/m2 from 53 species in the cleared plot. The soil seed bank was from mostly low density species with some high density species, and contained many pioneer species that were absent in the floor vegetation. Buried viable seeds were clumped together, especially in gravity-dispersal species. Although plenty of buried viable seeds were pooled in the soil, few seedlings emerged on the forest floor. In contrast, a number of seedlings, including many pioneer species, emerged in the cleared plots, showing a positive correlation between seed weight and germination rate. It is assumed that dominance of the seedlings established after clear-cutting depends on germination rates and/or growth rates of the seedlings rather than the initial density of buried viable seeds. These results suggest strong contribution of the soil seed bank to the establishment of the secondary vegetation after disturbance in a mature conifer plantation.

Do Blackburnian Warblers select mixed forest?: The importance of spatial resolution in defining habitat

Determining the importance of mixed forests to species diversity has become an important aspect of forest ecology and management. Mixed forests are vulnerable to silviculural practices that reduce heterogeneity. Thus, species associated with these forest types are of potential concern. To determine if Blackburnian Warblers ( Dendrioca fusca) select mixed forest, we examined habitat use at two spatial scales and resolutions across the full gradient of forest cover types using spot mapping, point counts, and behavioral observations. We detected no difference in abundance among cover types recognised at the resolution of the provincial air photo forest inventory (deciduous, conifer, and mixed forest). However, at finer resolutions, the species was more likely to occur in stands containing a combination of both deciduous and conifer trees. Territory locations were positively associated with deciduous tree height, conifer live crown width, and mature deciduous and conifer tree density. At the individual tree scale, Blackburnian Warblers were more likely to select mature conifer and deciduous trees for foraging and singing than immature conifers, but did not show preference for any tree type (i.e., deciduous or conifer).

Effects of precommercial thinning on snowshoe hare habitat use during winter in low-elevation montane forests

We assessed snowshoe hare (Lepus americanus L.) habitat use during winter on two precommercial thinning treatments in sapling stands in northwestern Montana, USA. One treatment type retained 0.2-ha patches of unthinned saplings, representing 8% of the total stand area, and the second retained 0.8-ha patches of unthinned saplings, representing 35% of the stand area. Snowshoe hare habitat use was also estimated within a nearby control sapling stand and mature conifer stands. We used snow tracking and fecal pellet counts to estimate use before and after thinning treatments were applied. Although we did not find a conclusive trend in hare use of sapling stands after thinning, use within the control stand and adjacent mature stands suggested there was considerable movement of hares to nearby untreated stands after thinning. Hares used retention patches regardless of size, even though large retention patches were four times larger than small retention patches. Because hares demonstrated an affinity for dense patches of residual forest, any retention of untreated saplings may be beneficial for hares during winter when applying precommercial thinning treatments in areas where stand sizes are relatively small (10–14 ha), and the resulting thinned matrix is less harsh than in larger thinned stands. Use within thinned portions of the stand and unthinned remnant blocks suggests that over the winter hares may also benefit from a connectivity of dense cover.

Harvesting and transport of root biomass from fast-growing poplar plantations

Recovery of tree root biomass can be attractive, since the stump-root system represents a substantial portion of the tree mass and its removal may prove instrumental to re-cultivation. Most available studies concern Nordic technologies, particularly suited to mature conifer stands. Unlike spruce, plantation poplar develops a deep taproot, whose extraction requires completely different methods. The aim of the study was to investigate poplar root recovery operations in plantations with time studies, and to determine the productivity and delivery costs of the operations. Seven operation systems developed to work with poplar plantations in Italian conditions were studied. Extraction and cleaning units were based on general-purpose prime movers. Under favourable conditions extraction and cleaning units achieved a very high productivity: 150 stumps per hour for the extraction unit and 170 for the cleaning unit. Delivered cost varied widely, ranging from 28 to 66 Euros Mg. Transportation was the most expensive single work task. It accounted for about 40% of the total recovery cost. Extraction and cleaning contributed approximately 25% each to the total cost, and loading 9%. Guidelines to recovery system improvement and efficient operation are provided.–1

Carbon and nitrogen dynamics in topsoils along forest conversion sequences in the Ore Mountains and the Saxonian lowland, Germany

Carbon and nitrogen stocks and their medium-term and readily decomposable fractions in topsoils were compared in relation to soil microbial biomass and activity along sequences from coniferous to deciduous stands. The study was carried out in the Ore Mountains and the Saxonian lowland, representing two typical natural regions in Saxony, Germany. In accordance with current forest conversion practices, the investigation sites represent different stands: mature conifer stands of Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris L.) (type A); Norway Scots spruce and pine with advanced plantings of European beech (Fagus sylvatica L.) or European beech/Common oak (Quercus petreae Liebl.) (type B); and mature deciduous stands of European beech and European beech/Common oak (type C). The investigated forest sites can be grouped into three silvicultural situations according to the development from coniferous stands to advanced plantings and finally mature deciduous forests (chronosequence A–B–C). The organic layer (L, F and H horizons) and uppermost mineral soil (0–10 cm) were analysed for potential C mineralisation, microbial biomass, concentrations of total C and N (TOC and TN) and for medium-term and readily decomposable C and N fractions, obtained by hot- and cold-water extraction respectively. The results showed an increase in organic layer thickness and mass as well as TOC and TN stocks along the forest sequences in the lowland. Yet, underplanted sites with two storeys revealed higher organic layer mass as well as TOC and TN stocks as compared to coniferous and deciduous stands. Stocks of hot- and cold-water-extractable C and N in relation to microbial biomass and its activity revealed a high turnover activity in deeper organic horizons of deciduous forests compared to coniferous stands. The stand-specific differentiation is discussed in relation to microbial biomass, litter quantity and quality and forest structure, but also with respect to the site-specific climatic factors and water budget as well as liming and fly-ash impacts. Results indicate higher dynamics in deciduous stands in the lowland especially during the initial turnover phase. The elevated microbial activity in deeper organic horizons of deciduous litter-influenced sites in spring is discussed as a specific indicator for long-term C sequestration potential as besides C mineralisation organic compounds are humified and thus, can be stored in the organic layer or in deeper soil horizons. Due to liming activities, stand-specific effects on organic matter turnover dynamics have evened out today in the Ore mountain region, but will presumably occur again once base saturation decreases. Here, the stand-specific effect on microbial biomass can currently be seen again as Cmic in the L horizon increased from spruce to beech. Our study sites in the lowland revealed no significant fly-ash impact. Differences between sites were evaluated by calculating the discriminance function. TOC and TN as well as medium-term degradable C and N were defined in this study as indicators for turnover dynamics along forest conversion sites.

Evaluation of mature conifer plantations as secondary habitat for epigeic forest arthropods (Coleoptera: Carabidae; Araneae)

Spiders (Araneae) and ground beetles (Coleoptera, Carabidae) were studied in a woodland of the Northwest German lowland. An ancient oak–beech stand (170 years old) growing on mineral soil as well as a 110-year-old Scots pine ( Pinus sylvestris) and a 55-year-old spruce ( Picea spp.) forest growing on peat were investigated by pitfall trapping. A total of 155 species (39 carabids, 116 spiders) and 16,887 individuals (5269 carabids, 11,618 spiders) was recorded. Beetle diversity was high in the oak–beech stand and the spruce forest, but significantly lower in the pine forest. In both conifer plantations the activity density of carabids was considerably lower. Spider diversity was significantly higher in the spruce forest when compared to the beech and pine stand, respectively. Analyses of assemblage similarity distinguished clearly the fauna of all three stands. For each forest type, indicator species were detected. Although both conifer plantations were planted on former bogs, spider species typical of bogs were present only in the pine stand, not in the spruce stand. In both animal taxa, species typical of deciduous forests were more numerous and abundant in the oak–beech stand when compared to the conifer plantations. Although they were in direct contact, the conifer stands on peat only to a very low extent serve as secondary habitats for the epigeic fauna of the autochthonous deciduous woodland. During the 1990s, various agricultural programmes in Central Europe promoted such conifer plantations – in contrast, such afforestation measures on extensively used or fallow land of former bogs are not supported by the results of this study.

Fluxes of trichloroacetic acid through a conifer forest canopy

Controlled-dosing experiments with conifer seedlings have demonstrated an above-ground route of uptake for trichloroacetic acid (TCA) from aqueous solution into the canopy, in addition to uptake from the soil. The aim of this work was to investigate the loss of TCA to the canopy in a mature conifer forest exposed only to environmental concentrations of TCA by analysing above- and below-canopy fluxes of TCA and within-canopy instantaneous reservoir of TCA. Concentrations and fluxes of TCA were quantified for one year in dry deposition, rainwater, cloudwater, throughfall, stemflow and litterfall in a 37-year-old Sitka spruce and larch plantation in SW Scotland. Above-canopy TCA deposition was dominated by rainfall (86%), compared with cloudwater (13%) and dry deposition (1%). On average only 66% of the TCA deposition passed through the canopy in throughfall and stemflow (95% and 5%, respectively), compared with 47% of the wet precipitation depth. Consequently, throughfall concentration of TCA was, on average, ∼1.4 × rainwater concentration. There was no significant difference in below-canopy fluxes between Sitka spruce and larch, or at a forest-edge site. Annual TCA deposited from the canopy in litterfall was only ∼1–2% of above-canopy deposition. On average, ∼800 μg m −2 of deposited TCA was lost to the canopy per year, compared with estimates of above-ground TCA storage of ∼400 and ∼300 μg m −2 for Sitka spruce and larch, respectively. Taking into account likely uncertainties in these values (∼±50%), these data yield an estimate for the half-life of within-canopy elimination of TCA in the range 50–200 days, assuming steady-state conditions and that all TCA lost to the canopy is transferred into the canopy material, rather than degraded externally. The observations provide strong indication that an above-ground route is important for uptake of TCA specifically of atmospheric origin into mature forest canopies, as has been shown for seedlings (in addition to uptake from soil via transpiration), and that annualized within-canopy elimination is similar to that in controlled-dosing experiments.

The classification of late seral forests in the Pacific Northwest, USA using Landsat ETM+ imagery

To conserve the Earth's most extraordinary expressions of temperate biodiversity in the Pacific Northwest (PNW), USA, the mapping of late seral (old and mature) conifer forests plays a critical role. For this paper, we define old conifer forests as >150 years and mature conifer forest between 50 and 150 years. We offer a new Optimal Iterative Unsupervised Classification (OIUC) procedure for mapping late seral conifer forests over an eight-ecoregion area. The key steps of the OIUC classification were: (1) fully using the Landsat 7 Enhanced Thematic Mapper Plus (ETM+) 15 m panchromatic channel merged with other 30 m bands 3 and 5 to make a pan-sharpened false color composite for high resolution image interpretation; (2) splitting the ETM+ scene by ecologically distinct areas, or ecoregions, to create relatively homologous images for classification; (3) using a procedure similar to cluster busting where multiple iterative manipulation of the ISODATA clusters was employed; and (4) edge matching of sub-scenes to form ecoregions, then later merged together to form a map for the entire PNW. Supporting data and information included ancillary spatial GIS data layers, aerial photos, Digital Ortho Quad images (DOQs), field investigations, and previously reported forest age results. Classification accuracy was assessed using 2081 stratified random locations on 105 individual DOQs covering the entire region. Approximately 4.7 million ha (∼19%) of the PNW was classified as old conifer forest (>150 years). Another 4.8 million ha (∼19%) was classified as mature conifer forest (50–150 years). Over 9.48 million ha (∼38%) of the PNW was late seral conifer forest. The extent of late seral forests (old and mature conifer cover classes) varied greatly between the eight ecoregions. The Central and Southern Cascades and Klamath–Siskiyou ecoregions contained the highest amount of late seral forest in the region. The results showed high accuracy of the late seral forest classification for the PNW with an overall accuracy of 90.72% and KAPPA test K value 0.8534. Producer's (Omission) accuracy for old and mature forests were 91.36% and 80.40%, User's (Commission) accuracy were 89.42% and 80.59%, respectively. Accuracy levels differed for the different ecoregions examined. In general, mature conifer forests exhibited higher levels of confusion than did old conifer forests, due to the spectral influences of high-density young conifer stands and terrain shadow effects. The results fill an important data gap needed for ongoing conservation planning purposes throughout the region. We found that for relatively large geographic areas the OIUC method is an efficient and cost-effective alternative that yields high quality results.

Forest resources variation along with the main rivers in typical forest region of Changbai Mountain

The restoration of the riparian vegetation disturbed by human activities is one of the hotspots of watershed ecology. Through interpreting the images of Remote Sensing in 1985 and 1999, the basic information of forest resources of Lushuhe Forest Bureau, which is a typical forest area of Chanbai Mountain was obtained with support of GIS. By dividing Land covers of Lushuihe area into 10 types (water body, residential land, stump land, farming land, wetland, mature conifer forest, midlife conifer forest, mature broadleaf forest, midlife broadleaf forest, and man-made young forest) and dividing the riparian zone into four buffers (in turn 1000, 2000, 3000, 4000 m away from the river), the changes of riparian forest resources during 1985–1999 were analyzed. The results showed that the deforestation intension has obviously decreased and the whole environment has been evidently improved, but the riparian ecosystem was still flimsy. In buffer 1, 2, 3 the area of midlife conifer forest increased largely, but the areas of other types of land covers all decreased. Midlife conifer forest had a comparatively good status in the three buffers. In buffer 4, midlife conifer forest, mature conifer forest, and mature broadleaf forest formed a forest-age rank that is helpful to stabilize the forest ecosystem and exert its functions. Area percentage of wetland decreased in buffer 1, buffer 2, and buffer 3, even in buffer 4 in which forest ecosystem rehabilitated comparatively well, so protecting and rehabilitating wetland is a very difficult task.