Forestry Roads Research Articles

Joints representation strategy: performance evaluation by a Finite Element code. A feasibility analysis of a tunnel infrastructure in the Carnian Alps

This study is part of a wider feasibility analysis of a new forestry road in the Dolomitic region. The investigated area is located in northeastern Italy, in the Carnic Alps complex geological context. The rock mass which would be crossed by the tunnel is a highly tectonized limestone characterized by a relatively high strength of the intact rock. The project focuses on the rock mass characterization and the modelling of its behavior by means of numerical simulations with a Finite Elements (FE) code. The generalized Hoek-Brown criterion is used, normal and shear stiffness of the joints are evaluated and different strategies for the representation of the rock mass discontinuities are adopted. The effects of two support systems, preliminary designed by a diffused simplified method, are evaluated focusing on the space around the tunnel, where the joints reach the critical state.

PERDAS DE SOLO, ÁGUA E NUTRIENTES POR EROSÃO HÍDRICA EM UMA ESTRADA FLORESTAL NA SERRA CATARINENSE

http://dx.doi.org/10.5902/1980509819616O uso do solo influencia a erosão hídrica, sendo que, em geral, em estradas dentro de áreas reflorestais são altas as perdas de solo, água e elementos químicos. O trabalho objetivou quantificar as perdas de solo, água e elementos químicos causadas pela erosão hídrica durante 17 meses, sob chuva natural, em uma estrada dentro de uma área de reflorestamento de pinus. O estudo foi realizado no município de Campo Belo do Sul – SC, na Florestal Gateados Ltda., em um solo Nitossolo Háplico típico. Para a coleta da água e do solo, foi utilizada a Roda Coshocton. As perdas de solo foram de 19,65 t ha-1, enquanto as perdas de água equivaleram a 37% do volume de chuva precipitado no período experimental. Houve correlação linear e positiva entre altura de chuva e perdas de água por escoamento superficial, entre altura de chuva e perdas de solo por erosão, e entre perdas de solo e perdas de água por erosão hídrica. Os teores dos elementos químicos estudados em geral foram altos nos sedimentos da erosão hídrica, superiores aos teores encontrados na camada superficial do solo na qual a erosão se originou e muito superiores aos encontrados na água da enxurrada. Portanto, para sistemas de exploração do solo em que as perdas de sedimentos são altas, como é o caso de estradas florestais, as perdas de nutrientes causadas pela erosão hídrica estão mais relacionadas às perdas de sedimentos do que às perdas de água.

Future Forest Cover Change Scenarios with Implications for Landslide Risk: An Example from Buzau Subcarpathians, Romania.

This study focuses on future forest cover change in Buzau Subcarpathians, a landslide prone region in Romania. Past and current trends suggest that the area might expect a future increase in deforestation. We developed spatially explicit scenarios until 2040 to analyze the spatial pattern of future forest cover change and potential changes to landslide risk. First, we generated transition probability maps using the weights of evidence method, followed by a cellular automata allocation model. We performed expert interviews, to develop two future forest management scenarios. The Alternative scenario (ALT) was defined by 67% more deforestation than the Business as Usual scenario (BAU). We integrated the simulated scenarios with a landslide susceptibility map. In both scenarios, most of deforestation was projected in areas where landslides are less likely to occur. Still, 483 (ALT) and 276 (BAU) ha of deforestation were projected on areas with a high-landslide occurrence likelihood. Thus, deforestation could lead to a local-scale increase in landslide risk, in particular near or adjacent to forestry roads. The parallel process of near 10% forest expansion until 2040 was projected to occur mostly on areas with high-landslide susceptibility. On a regional scale, forest expansion could so result in improved slope stability. We modeled two additional scenarios with an implemented landslide risk policy, excluding high-risk zones. The reduction of deforestation on high-risk areas was achieved without a drastic decrease in the accessibility of the areas. Together with forest expansion, it could therefore be used as a risk reduction strategy.

К вопросу разработки методики корректирования режимов технического обслуживания лесовозных автопоездов

К вопросу разработки методики корректирования режимов технического обслуживания лесовозных автопоездов

К вопросу исследования эксплуатационной надежности лесовозных автопоездов

К вопросу исследования эксплуатационной надежности лесовозных автопоездов

Suspended sediment inflow into a stream through a forestry road from a thinned stand – a case in Ikutahara National Forest –

Suspended sediment inflow into a stream through a forestry road from a thinned stand – a case in Ikutahara National Forest –

EROSÃO HÍDRICA EM PLANTIO DE PINUS, EM ESTRADA FLORESTAL E EM CAMPO NATIVO

Santa Catarina é o terceiro exportador de produtos florestais, com 320 mil ha (11%) das florestas plantadas brasileiras. Somente na região de Lages, SC, existem 70 milhões de árvores de pinus plantadas, o que faz dessa região a terceira do mundo em área florestada com essa espécie, atrás de Finlândia e Suécia. O trabalho objetivou quantificar a erosão hídrica durante 17 meses (entre setembro de 2009 e janeiro de 2011), sob chuva natural, em reflorestamento de pinus com diferentes idades, em uma estrada de uso florestal e em campo nativo, no município de Campo Belo do Sul, SC, na empresa “Florestal Gateados” Ltda., em que a enxurrada foi coletada com uma Roda Coshocton. As perdas de água por escoamento superficial foram de 6 mm no pinus de três anos, de 13 mm no campo nativo, de 23 mm no pinus de 10 meses e 157 mm no pinus de 26 anos, consideradas muito baixas em relação à precipitação ocorrida no período experimental, que foi de 2.040 mm, enquanto que na estrada florestal as perdas de água foram de 928 mm, consideradas altas. Quanto às perdas de solo, elas foram de 8 kg.ha-1 no pinus de três anos, 28 kg.ha-1 no campo nativo, 40 kg.ha-1 no pinus de 26 anos e 74 kg.ha-1 no pinus de 10 meses, também consideradas muito baixas em relação à tolerância de perda de solo, enquanto que na estrada florestal as perdas de solo foram de 22.000 kg.ha-1, consideradas altas.Palavras-chave: Perdas de solo e água; Roda Coshocton; reflorestamentos. AbstractHidric erosion in pinus culture, in forestry road and native grassland. Santa Catarina is the third Brazilian state in exporting forestry products, with 320,000 hectares (11%) of Brazilian forests. Only in Lages there are 70 millions of pinus trees, and it is the third region with the greater density forested area in the world, just losing to Finland and Sweden. This research had as objective to quantify rainfall erosion during 17 months (from September, 2009 to January, 2011), under natural rain, in pinus reforestation areas with different ages, in a forestry road and natural grasslands, in Campo Belo do Sul/SC - Florestal Gateados Ltda., where the runoff was collected by Coshocton wheels. Water loss by runoff was 6 mm for three years-old pinus, 13 mm for natural grasslands, 23 mm for ten months-old pinus trees and 157 mm for 26 years-old pinus; all of them were considered small due to the rainfall which occurred during the experiment period (2.040 mm); however, in the forestry road, water loss was considered higher (928 mm). In relation to soil losses, those were 8 kg.ha-1 for three years-old pinus, 28 kg.ha-1 for natural grasslands, 40 kg.ha-1 for 26 years-old pinus and 74 kg.ha-1 for ten months-old pinus trees; all of them were considered small in relation to the tolerance of soil loss; however, in the forestry road, soil loss was considered higher (22.000 kg.ha-1).Keywords: Soil and water losses; Coshocton weels; reforestation.

Impacts of Human Disturbance on Large Prey Species: Do Behavioral Reactions Translate to Fitness Consequences?

Anthropogenic disturbances have been demonstrated to affect animal behavior, distribution, and abundance, but assessment of their impacts on fitness-related traits has received little attention. We hypothesized that human activities and infrastructure cause a decrease in the individual performance of preys because of anthropogenically enhanced predation risk. We evaluated the impacts of commercial logging and road networks on the fitness of a large herbivore known to be sensitive to human disturbance: the forest-dwelling woodland caribou (Rangifer tarandus caribou). For 8 consecutive years (2004–2011) we monitored 59 individuals using GPS telemetry in the Charlevoix region of Québec, Canada. We also used Very High Frequency telemetry locations collected on 28 individuals from 1999–2000. We related habitat selection of adult caribou at various spatio-temporal scales to their probability of dying from predation, and to indices of their reproductive success and energy expenditure. The probability that adult caribou died from predation increased with the proportion of recent disturbances (including cutblocks ≤5 years old) in their annual home range. The respective effects of increasing paved and forestry road densities depended upon the overall road density within the home range of caribou. At a finer scale of 10 to 15 days before their death, caribou that were killed by a predator selected for recent disturbances more than individuals that survived, and avoided old mature conifer stands. The home range area of caribou increased with road density. Finally, the composition of the home range of females had no effect on their reproductive success. We show that human activities and infrastructure may influence the individual performance of large prey species in highly managed regions. We outline the need to consider the full set of impacts that human development may have on threatened animal populations, with particular emphasis on predator-prey relationships and population dynamics.

Habitat fragmentation in forests affects relatedness and spatial genetic structure of a native rodent, Rattus lutreolus

AbstractHabitat fragmentation can have a range of negative demographic and genetic impacts on disturbed populations. Dispersal barriers can be created, reducing gene flow and increasing population differentiation and inbreeding in isolated habitat remnants. Aggregated retention is a form of forestry that retains patches of forests as isolated island or connected edge patches, with the aim of ‘lifeboating’ species and processes, retaining structural features and improving connectivity. Swamp rats (Rattus lutreolus) are a cover‐dependent species that are sensitive to habitat removal. We examined the effects of aggregated retention forestry and forestry roads in native wet Eucalyptus forests on swamp rat gene flow and population genetic structure. We characterized neighbourhood size in unlogged forest to provide a natural state for comparison, and examined population structure at a range of spatial scales, which provided context for our findings. Tests of pairwise relatedness indicated significant differentiation between island and edge populations in aggregated retention sites, and across roads in unlogged sites. Spatial autocorrelation suggested a neighbourhood size of 42–55 m and revealed male‐biased dispersal. We found no genetic isolation by geographical distance at larger (>2.3 km) scales and populations were all significantly differentiated. Our results suggest that removal of mature forest creates barriers for swamp rat dispersal. In particular, roads may have long‐term impacts, while harvesting of native forests is likely to create only short‐term dispersal barriers at the local scale, depending on the rate of regeneration.

Study of The Nature of Urban Flood In Benin City, Edo State; Nigeria

The Niger Delta region of Nigeria is mostly flat, low lying, swampy basin resulting in severe regular flooding which has led to a limited land area available for human habitat. Approximately 7000km2 of land cannot be used owing to flooding. This study assessed the nature of urban flood in Benin City, Edo State; Nigeria. Thirty-five streets and roads were identified as areas prone to regular flooding and twelve of these streets including Uselu – Ugbowo Road, New Lagos- Uselu Road, Sakpoba – Oka Road, Plymouth – Oliha Road, Uwasota-Ogida road, Ogida-textile-Urubi Road, Television Road, Erhummunse Road, Upper Mission Road, Wire road, Forestry Road were identified as the most critical. The types of flood experienced are flash flood and flood pondages. 52% of the total area is inundated for more than two hours during flood episodes with an average water height of 1m. Laboratory analyses of soil samples collected from the twelve streets and roads show a greater clay fraction than any other soil fraction with clay as 52.23%, sand 28% and silt 19%. Permeability is low with a value of 1.17 x 10-3cm/sec. Bulk density ranged from 1.9gcm3 at Forestry road to 3.12gcm3 at Sakpoba – Okah road. The degree of variability between and within locations of the factors of flooding in Benin City showed that there is no significant variation between the locations of the flooded area in Benin City at P>0.05 level of significance. However, there was significant difference in the variation among the parameters with Clay varying significantly at P>0.05 level of significance from all others, while silt and sand are not different from each other as similarities exist between the other parameters. By this implication, Clay is the dominant soil type of the study area. In consonance with dominance of the clay soil in the study area, bulk density is high. It is therefore concluded that the soil condition is a major determinant of flooding in Benin City. The flooding problems has resulted in traffic congestion and lost of man-hours giving rise to lopsided concentration of vehicular traffic.

Evaluation of forestry roads as feeding sites of sika deer

Evaluation of forestry roads as feeding sites of sika deer

The Effect of Forestry Roads on Access to Remote Fishing Lakes in Northern Ontario, Canada

AbstractLakes without road or vehicular trail access (i.e., remote lakes) are becoming increasingly scarce in North America. In the Boreal Shield, road construction for forestry operations is probably the prime factor affecting the scarcity of remote lakes. To assess the effects of forestry roads on lake access, this paper develops and tests a model that predicts the occurrence of road or vehicular trail access to lakes in northern Ontario. The results of a probit model support the hypothesis that increased forestry activity near lakes (as measured by road density within 1 km of the lake and the proximity of the lake to two‐lane roads) results in increased likelihood of access. We also hypothesized that lake size, the presence of particular fish species, and the proximity of the lake to human communities would increase the likelihood of access. Except for no effect from the presence of trout Salvelinus species, the analyses supported these hypotheses. The predictive validity of the model was tested with holdout data from two other areas of northern Ontario. Strong support for the model was found from analyses of receiver operating characteristic curves for the two holdout data sets. Management scenarios from the model were used to illustrate the potential effects of forestry roads on access development to remote lakes. Our model predicts that in areas where forestry operations occur, development of access to lake shorelines will probably occur, especially on large‐sized lakes containing walleyes Sander vitreus. Proactive management involving the closure of forestry roads is probably needed to retain remote lakes in areas with high levels of forestry activity.

Dispersal ofCulex quinquefasciatus(Diptera: Culicidae) in a Hawaiian Rain Forest

Introduced mosquito-borne pathogens avian malaria (Plasmodium relictum Grassi and Feletti) and avian pox virus (Avipoxvirus) have been implicated in the past extinctions and declines of Hawaiian avifauna and remain significant obstacles to the recovery and restoration of endemic Hawaiian birds. Effective management of avian disease will require extensive mosquito control efforts that are guided by the local ecology of the vector Culex quinquefasciatus Say (Diptera: Culicidae). During October and November 1997 and September through November 1998 five mark-release–recapture experiments with laboratory-reared Cx. quinquefasciatus were conducted in a native rain forest on Hawaii Island. Of the overall 66,047 fluorescent dye-marked and released females, 1,192 (1.8%) were recaptured in 43-52 CO2-baited traps operated for 10–12-d trapping periods. Recaptured mosquitoes were trapped in all directions and at distances up to 3 km from the release site. The cumulative mean distance traveled (MDTs) over the trapping period ranged from a high of 1.89 km after 11 d (September 1998) to a low of 0.81 km after 11 d (November 1998). Released mosquitoes moved predominately in a downwind direction and they seemed to use forestry roads as dispersal corridors. Applying an estimated MDT of 1.6 km to a geographical information system-generated map of the Hakalau Forest National Wildlife Refuge clearly demonstrated that the effective refuge area could be reduced 60% by mosquitoes infiltrating into managed refuge lands. These findings should have significant implications for the design of future refuges and development of effective mosquito-borne avian disease control strategies.

Dispersal of <I>Culex quinquefasciatus</I> (Diptera: Culicidae) in a Hawaiian Rain Forest

Introduced mosquito-borne pathogens avian malaria (Plasmodium relictum Grassi and Feletti) and avian pox virus (Avipoxvirus) have been implicated in the past extinctions and declines of Hawaiian avifauna and remain significant obstacles to the recovery and restoration of endemic Hawaiian birds. Effective management of avian disease will require extensive mosquito control efforts that are guided by the local ecology of the vector Culex quinquefasciatus Say (Diptera: Culicidae). During October and November 1997 and September through November 1998 five mark-release-recapture experiments with laboratory-reared Cx. quinquefasciatus were conducted in a native rain forest on Hawaii Island. Of the overall 66,047 fluorescent dye-marked and released females, 1,192 (1.8%) were recaptured in 43-52 CO2-baited traps operated for 10-12-d trapping periods. Recaptured mosquitoes were trapped in all directions and at distances up to 3 km from the release site. The cumulative mean distance traveled (MDTs) over the trapping period ranged from a high of 1.89 km after 11 d (September 1998) to a low of 0.81 km after 11 d (November 1998). Released mosquitoes moved predominately in a downwind direction and they seemed to use forestry roads as dispersal corridors. Applying an estimated MDT of 1.6 km to a geographical information system-generated map of the Hakalau Forest National Wildlife Refuge clearly demonstrated that the effective refuge area could be reduced 60% by mosquitoes infiltrating into managed refuge lands. These findings should have significant implications for the design of future refuges and development of effective mosquito-borne avian disease control strategies.

Effetto del regime luminoso sulla rinnovazione naturale dell’abete bianco (Abies alba Mill.) nel bosco di Archiforo, Calabria

Abstract: Aim of this study is to analyse the effect of light environment on dynamics of natural regeneration of silver fir. The study areas were located in natural silver fir (Abies alba Mill.) stands of Serra San Bruno Forests (Archiforo) in the Calabrian Apennine. Measurements of the Photosynthetically Active Radiation (PAR - radiation in the 0.4-0.7 µm waveband) were collected with a ceptometer (AccuPAR Decagon Devices, USA). PAR was measured monthly during the growing season. Measurements were taken: under canopy, inside natural gaps and in correspondence of escarps along forestry roads. After each measurement for each sampling point the PAR transmittance was calculated. Seedlings density was estimated in each position. Each of these seedlings was identified by species, total height was measured and the age was visually determined. Seedlings were distributed in three classes: (a) class 0: to natural regeneration absence and height 10 seedlings m-2 and height between 0.30 and 1 m; (c) class 2: to density > 10 seedlings m-2 and height > 1 m. Level of PAR transmittance was higher inside the gaps where a good seedlings density was observed. Further seedling density was higher in correspondence of escarps. Under canopy, seedlings were absent due to low levels of light (1.3 < T < 3.7). The results showed a diverse ecological behaviour to light environment of silver fir of Serra San Bruno compared with central-northern Abies alba population. Some comments about silvicultural treatment of silver fir stand in the Calabrian Apennine are provided, according to dynamics of natural regeneration.

Example of a debris-flow risk analysis from Vancouver Island, British Columbia, Canada

In July 2005, a debris flow and a water flood occurred on two adjacent gullies in the White River area, on northern Vancouver Island in British Columbia, Canada. The 16,000 m3 debris flow buried approximately 7.5 ha of second-growth trees, buried approximately 500 m of a forestry road, and reached two fish-bearing streams. The water flood eroded approximately 240 m of the same forestry road and plugged four culverts before overtopping and inundating the road. To better plan for future events, risk analyses of debris flows, debris floods, and water floods were carried out for the two gullies involved, plus a third adjacent gully. The elements at risk that were analyzed included, in order of priority: users of the forestry road, the fish-bearing streams, the forestry road itself, and a timber bridge. Using a series of qualitative, but defined, relative-risk matrices, the following components of specific risk were estimated for each of the three types of events on each of the three gullies for each of the four elements at risk: probability of occurrence, probability that the event will reach or otherwise affect the site of the element at risk, the probability that the element at risk will be at the site when the event occurs, and the probability of loss or damage resulting from the element being at the site when the event occurs.

Runoff, sediment loss and water quality from forest roads in a southeast Queensland coastal plain Pinus plantation

Runoff and sediment loss from forest roads were monitored for a two-year period in a Pinus plantation in southeast Queensland. Two classes of road were investigated: a gravelled road, which is used as a primary daily haulage route for the logging area, and an ungravelled road, which provides the main access route for individual logging compartments and is intensively used as a haulage route only during the harvest of these areas (approximately every 30 years). Both roads were subjected to routine traffic loads and maintenance during the study. Surface runoff in response to natural rainfall was measured and samples taken for the determination of sediment and nutrient (total nitrogen, total phosphorus, dissolved organic carbon and total iron) loads from each road. Results revealed that the mean runoff coefficient (runoff depth/rainfall depth) was consistently higher from the gravelled road plot with 0.57, as compared to the ungravelled road with 0.38. Total sediment loss over the two-year period was greatest from the gravelled road plot at 5.7 t km −1 compared to the ungravelled road plot with 3.9 t km −1. Suspended solids contributed 86% of the total sediment loss from the gravelled road, and 72% from the ungravelled road over the two years. Nitrogen loads from the two roads were both relatively constant throughout the study, and averaged 5.2 and 2.9 kg km −1 from the gravelled and ungravelled road, respectively. Mean annual phosphorus loads were 0.6 kg km −1 from the gravelled road and 0.2 kg km −1 from the ungravelled road. Organic carbon and total iron loads increased in the second year of the study, which was a much wetter year, and are thought to reflect the breakdown of organic matter in roadside drains and increased sediment generation, respectively. When road and drain maintenance (grading) was performed runoff and sediment loss were increased from both road types. Additionally, the breakdown of the gravel road base due to high traffic intensity during wet conditions resulted in the formation of deep (10 cm) ruts which increased erosion. The Water Erosion Prediction Project (WEPP):Road model was used to compare predicted to observed runoff and sediment loss from the two road classes investigated. For individual rainfall events, WEPP:Road predicted output showed strong agreement with observed values of runoff and sediment loss. WEPP:Road predictions for annual sediment loss from the entire forestry road network in the study area also showed reasonable agreement with the extrapolated observed values.

Managing Environmental Impacts of Recreation and Tourism in Rainforests of the Wet Tropics of Queensland World Heritage Area

AbstractThis paper describes environmental impacts of tourism and recreation activities in the world heritage listed rainforests of northeast Australia and presents management strategies for sustainable visitor use of the protected area. Tropical rainforests are characterised by their low resistance and moderate to high resilience to impacts associated with human visitation. Visitor use in the World Heritage Area is mostly associated with walking tracks, camping areas, day use areas and off‐road vehicle use of old forestry roads and tracks. Adverse environmental impacts range from vegetation trampling, soil compaction, water contamination and soil erosion at the local scale through to spread of weeds, feral animals and soil pathogens along extensive networks of old forestry roads and tracks at the regional scale. Concentration of visitor use is the most desirable management strategy for controlling adverse impacts at most World Heritage Area visitor nodes and sites, and includes methods such as site hardening and shielding to contain impacts. For dispersed visitor activities, such as off‐road vehicle driving and long‐distance walking, application of best practice methods by the tourist industry and recreational users such as removal of mud and soils from vehicle tyres and hiking boots before entering pathogen‐free catchments, together with seasonal closure of roads and tracks, are the preferred management strategies. Retention of canopy cover at camping areas and day use areas, as well as along walking tracks and forestry roads is a simple, yet effective, management strategy for reduction of a range of adverse impacts, including dispersal of weeds and feral animals, edge effects, soil erosion and nutrient loss, road kill and linear barrier effects on rainforest fauna.

Grizzly bear use of open, closed, and restricted forestry roads

We investigated grizzly bear (Ursus arctos) selection of three road types in the northern United States and southern British Columbia from 1986 to 1991. We hypothesized that grizzly bears select against open (public use allowed), restricted (forestry use only), and closed roads (no public use allowed) in that order. We analyzed use of roads for 11 bears (five females and six males) in an area containing open and closed roads and 11 bears (seven females and four males) in an adjacent area containing restricted roads. We used χ2 and log–linear models to test for selection of habitat type and distance to road categories. Ten of 12 females and 5 of 10 males (15 of 22 bears) selected against (P &lt; 0.05) low-elevation interior cedar-hemlock and for (P &lt; 0.05) high-elevation Englemann spruce (Picea engelmannii Parry ex Engelm.) – subalpine fir (Abies lasiocarpa (Hook.) Nutt.). After accounting for habitat, 4 of 5 females and 3 of 6 males (7 of 11 bears) selected against open roads and 3 of 5 females and 0 of 6 males (3 of 11 bears) selected against closed roads. No females (n = 7) or males (n = 4) (0 of 11 bears) selected against restricted roads. Our results are inconsistent with the hypothesis that bears select against open, restricted, and closed roads in that order. Most females and males selected against open roads, most females selected against closed roads, and no bears selected against restricted roads. The type of human activity along roads plays a role in bear responses to roads, and this aspect should be incorporated into future bear-road studies.

Effects of forestry roads on reproductive habitat and exploitation of lake trout (Salvelinus namaycush) in three experimental lakes

This study was designed to test the effects of two potential impacts of forest access roads on lake trout (Salvelinus namaycush) lakes in the Boreal Shield ecozone: (i) loss of reproductive habitat through siltation and (ii) increased access and exploitation. During an 9-year study (1991-1999) in Whitepine Lake, access to seven original spawning sites and over 250 alternate spawning sites was progressively removed by covering the substrate with opaque plastic sheeting to simulate siltation. No effects on recruitment of lake trout have yet been detected. Mark-recapture estimates of juvenile (&lt;370 mm fork length) abundance remained high, mean body size did not increase, and emergent alevins continued to be produced from the alternate spawning sites each year. Similar results occurred in a short-term study in Helen Lake. The lack of obvious effects of reproductive habitat loss was in sharp contrast with the rapid and severe effects that fishing pressure exerted on the lake trout population in Michaud Lake where access was improved by construction of a 12-km forest access road. These findings suggest that lake trout can tolerate substantial losses in spawning habitat, but natural populations, particularly in small lakes, must be protected from excessive exploitation.