Forest Landscape Pattern Research Articles

Forest Landscape Patterns around Marbled Murrelet Nest Sites in the Oregon Coast Range

We analyzed forest composition and landscape preferences of marbled murrelets (Brachyramphus marmoratus). Using dawn surrreys and tree climbing, we found 41 murrelet nest sites on state and federal lands in the Oregon Coast Range Province in western Oregon between 1990 and 1998. Landscapes in 0.5- and 1.0-km-radius plots at these nest sites were compared to patterns in similar plots around a set of points randomly selected from stands of mature or old- growth trees on public lands in the same province. We found less open-sapling and hardwood forests in the plots at nest sites than at random sites for both plot sizes. Conversely, the pro- portion of pole-young conifer habitat was greater at nest sites than at random sites for both plot sizes. Landscape pattern analysis showed that the amount of edge-perimeter density, nest-patch perimeter, and high-contrast edge of nest patches was lower in the 1.0-km-radius plots at nest sites than at random sites. Our best multivariate logistic regression model indicated that greater amounts of pole-young and mature-old-growth forests, less edge (perimeter density and high- contrast edge at nest patches), and more cohesive nest-patch shape best distinguished murrelet nest sites from random sites. We hypothesize that murrelet nest-site selection at the landscape scale may be the result of an antipredator strategy to reduce predation risks on eggs and juvenile murrelets. Young (simple-structure) conifer stands adjacent to nesting areas may decrease pre- dation rates at murrelet nests. Land managers should consider limiting clearcut harvest units both adjacent to murrelet nest patches and within at least 1 km of murrelet nests, as clearcuts increase high-contrast edge in addition to increasing fragmentation levels.

Self-organized criticality in forest-landscape evolution

A simple cellular automaton replicates the fractal pattern of a natural forest landscape and predicts its evolution. Spatial distributions and temporal fluctuations in global quantities show power-law spectra, implying scale-invariance, characteristic of self-organized criticality. The evolution toward the SOC state and the robustness of that state to perturbations are described.

CAN FOREST MANAGEMENT SAFELY EMULATE NATURAL DISTURBANCES AND LANDSCAPE PATTERNS IN PRECAMBRIAN SHIELD SHORELINE FORESTS?

CAN FOREST MANAGEMENT SAFELY EMULATE NATURAL DISTURBANCES AND LANDSCAPE PATTERNS IN PRECAMBRIAN SHIELD SHORELINE FORESTS?Shoreline (riparian) forests are not excluded from Ontario's Crown Forest Sustainability Act (CFSA) requirement to emulate natural disturbance and landscape patterns during forest management. In boreal forests of Ontario, efficient fire suppression is combined with management policies that prescribe 30 to 90 m forested shoreline reserves around most lakes > 10 ha in size. These shoreline...Author(s)Robert J. SteedmanRobert S. RempelSourceProceedings of the Water Environment FederationSubjectSession 25 - Effectiveness of Best Management PracticesDocument typeConference PaperPublisherWater Environment FederationPrint publication date Jan, 2000ISSN1938-6478SICI1938-6478(20000101)2000:6L.2474;1-DOI10.2175/193864700785150376Volume / Issue2000 / 6Content sourceWatershed ConferenceFirst / last page(s)2474 - 2479Copyright2000Word count248

The influence of forest fragmentation and landscape pattern on American martens

1. We investigated the effects of forest fragmentation on American martens (Martes americana Rhoads) by evaluating differences in marten capture rates (excluding recaptures) in 18 study sites with different levels of fragmentation resulting from timber harvest clearcuts and natural openings. We focused on low levels of fragmentation, where forest connectivity was maintained and non‐forest cover ranged from 2% to 42%. 2. Martens appeared to respond negatively to low levels of habitat fragmentation, based on the significant decrease in capture rates within the series of increasingly fragmented landscapes. Martens were nearly absent from landscapes having > 25% non‐forest cover, even though forest connectivity was still present. 3. Marten capture rates were negatively correlated with increasing proximity of open areas and increasing extent of high‐contrast edges. Forested landscapes appeared unsuitable for martens when the average nearest‐neighbour distance between open (non‐forested) patches was <100 m. In these landscapes, the proximity of open areas created strips of forest edge and eliminated nearly all forest interior. 4. Small mammal densities were significantly higher in clearcuts than in forests, but marten captures were not correlated with prey abundance or biomass associated with clearcuts. 5. Conservation efforts for the marten must consider not only the structural aspects of mature forests, but the landscape pattern in which the forest occurs. We recommend that the combination of timber harvests and natural openings comprise <25% of landscapes ≥9 km2 in size. 6. The spatial pattern of open areas is important as well, because small, dispersed openings result in less forest interior habitat than one large opening at the same percentage of fragmentation. Progressive cutting from a single patch would retain the largest amount of interior forest habitat.

Pattern and change of a boreal forest landscape in northeastern China

Pattern and change of a boreal forest landscape in northeastern China

Pathogens, Patterns, and Processes in Forest Ecosystems

lthough pathogens are regarded as agents responsible for the specific dynamics of natural forest communities (Dickman 1992, Dinoor and Eshed 1984, Haack and Byler 1993, van der Kamp 1991), they have received little attention at the landscape level, especially compared to catastrophic abiotic disturbances, such as fire and blowdowns (Foster and Boose 1992, Heinselman 1973). With so much emphasis today on ecosystem management and the maintenance of natural disturbance regimes, the role of pathogens deserves careful scrutiny. Pathogens (biotic agents that incite disease) differ from many abiotic disturbances by selectively eliminating the less vigorous or genetically unfit individuals of a population, yet the biotic and abiotic agents are similar in that both function to recycle essential elements and to alter forest development and landscape patterns. Pathogen interaction with abiotic disturbance to control the direction and rate of forest succession also has received minimal attention, although such

Measuring forest landscape patterns in the cascade range of Oregon, USA

This paper describes the use of a set of spatial statistics to quantify the landscape pattern caused by the patchwork of clearcuts made over a 15-year period in the western Cascades of Oregon. Fifteen areas were selected at random to represent a diversity of landscape fragmentation patterns. Managed forest stands (patches) were digitized and analysed to produce both tobular and mapped information describing patch size, shape, abundance and spacing, and matrix characteristics of a given area. In addition, a GIS fragmentation index was developed which was found to be sensitive to patch abundance and to the spatial distribution of patches. Use of the GIS-derived index provides an automated method of determining the level of forest fragmentation and can be used to facilitate spatial analysis of the landscape for later coordination with field and remotely sensed data. A comparison of the spatial statistics calculated for the two years indicates an increase in forest fragmentation as characterized by an increase in mean patch abundance and a decrease in interpatch distance, amount of interior natural forest habitat, and the GIS fragmentation index. Such statistics capable of quantifying patch shape and spatial distribution may prove important in the evaluation of the changing character of interior and edge habitats for wildlife.