Showing papers in "Canadian Journal of Forest Research in 1995"
TL;DR: A linear mixed-effects model that accounts for the covariances among repeated measurements and for random plot effects is developed with a continuous-time autocorrelation error structure and shows marked improvement compared with models that do not account for the error structure.
Abstract: A linear mixed-effects model that accounts for the covariances among repeated measurements and for random plot effects is developed. A continuous-time autocorrelation error structure permits the mo...
290 citations
TL;DR: The results suggest that forest composition at both the stand and the forest mosaic levels may be responsible for differing degrees of defoliation that result in differences in different degrees in balsam fir mortality.
Abstract: Balsam fir (Abiesbalsamea (L.) Mill.) mortality caused by the last spruce budworm (Choristoneurafumiferana (Clem.)) outbreak (1970–1987) was studied in 624 sites belonging to a complex natural forest mosaic originating from different fires in northwestern Quebec. Multiple regression analyses were used to assess the respective effects of stand structure, species composition, site characteristics, and the forest composition surrounding the stand on observed stand mortality. Mortality was observed to increase in relation to diameter of the trees, basal area of balsam fir, and the number of stands dominated by conifers in the forest mosaic. All of these factors showed significant independent effects, but 60% of the variance remained unexplained. Site characteristics, however, did not show a significant relationship to stand mortality. The results suggest that forest composition at both the stand and the forest mosaic levels may be responsible for differing degrees of defoliation that result in differences in ...
193 citations
TL;DR: Forest landscape management is based on the premise that resource flows as well as biodiversity levels and ecosystem processes are determined by the array and spatial arrangement of forest conditio... as mentioned in this paper.
Abstract: Forest landscape management is based on the premise that resource flows as well as biodiversity levels and ecosystem processes are determined by the array and spatial arrangement of forest conditio...
180 citations
TL;DR: Mean daily percent PPFD did not vary significantly between the different sensor locations within closed pine stands, indicating that at high latitudes mean daily percentPPFD does not vary much spatially under closed Scots pine stands.
Abstract: Spatial and temporal variations in photosynthetic photon flux density (PPFD) at 1 m above the forest floor were measured under and between dominant pines and in 21- to 52-m2 gaps under developing Scots pine (Pinussylvestris L.) stands in southern Finland. For each stand, PPFD data were collected continuously every 10-s and then averaged for every 5-min period during 4-6 days under completely clear and overcast sky conditions. Measurements were made during 102 consecutive days within two different areas in each of 10 different Scots pine stands ranging in age from 7 to 105 years. Mean daily percent PPFD in the understory varied from 7.5% in the 20-year-old stands to 38% in the 7-year-old stands, and did not differ significantly between completely clear and overcast sky conditions. Mean daily percent PPFD did not vary significantly between the different sensor locations within closed pine stands, indicating that at high latitudes mean daily percent PPFD does not vary much spatially under closed Scots pine f...
164 citations
TL;DR: Measurements of aboveground biomass and nitrogen (N) nutrition were made during July 1993 in 50, 130, and 380-year-old stands of Larixgmelinii (Rupr.) Rupr.
Abstract: Measurements of aboveground biomass and nitrogen (N) nutrition were made during July 1993 in 50-, 130-, and 380-year-old stands of Larixgmelinii (Rupr.) Rupr. in eastern Siberia. Constituting six f...
146 citations
TL;DR: In this paper, the authors quantified stand leaf area index and vertical leaf area distribution, and developed canopy extinction coefficients (k) in four mature hardwood stands, and calculated the index from litter data.
Abstract: We quantified stand leaf area index and vertical leaf area distribution, and developed canopy extinction coefficients (k), in four mature hardwood stands. Leaf area index, calculated from litter fa...
134 citations
TL;DR: The effects of drought on growth of red oak group species were studied by examining basal area increment and ring width index patterns of dominant Quercuscoccinea Muenchh.
Abstract: The effects of drought on growth of red oak group species were studied by examining basal area increment and ring width index patterns of dominant Quercuscoccinea Muenchh. (scarlet oak) and Quercus...
128 citations
TL;DR: In this paper, the authors analyzed witness-tree data recorded from 1765 to 1798 with respect to landform in four major physiographic provinces represented through north central Pennsylvania and compared with present-day forest composition to evaluate broad changes that occurred 200 years after European settlement.
Abstract: This study analyzed witness-tree data recorded from 1765 to 1798 with respect to landform in four major physiographic provinces represented through north central Pennsylvania. These data were also compared with present-day forest composition to evaluate broad changes that occurred 200 years after European settlement. In the Allegheny High Plateau, Tsugacanadensis (L.) Carr. represented 40–47% of witness trees in mountain coves and stream valleys, but only 9% on plateau tops, which comprised 45% Fagusgrandifolia Ehrh. Pinusstrobus L. represented ≤4% frequency across all landforms. The original forests of the Allegheny Mountains were dominated by mixed Quercus, Acer, Castaneadentata (Marsh.) Borkh., and Pinus and had significant T. canadensis only in stream valleys. The presettlement forests of the Allegheny Front and the Ridge and Valley provinces had a similar mix of Quercus, Pinus, Castanea, and Carya, with increased P. strobus on the more mesic sites and Pinusrigida Mill, on the xeric ridges. Comparison...
122 citations
TL;DR: The effect of red alder (Alnusrubra Bong) on soil phosphorus availability in conifer forests of the Pacific Northwest has been the focus of several recent studies as mentioned in this paper.
Abstract: The effect of red alder (Alnusrubra Bong.) on soil phosphorus (P) availability in conifer forests of the Pacific Northwest has been the focus of several recent studies. One study at the Thompson Research Center in Washington State, found Bray No. 2 extractable P to be lower in soils under pure alder than in soils under adjacent stands of pure conifer. The Thompson study, and others in forests of the Northwest, have also found that the quantity of P in aboveground litter fall is greater for conifer stands mixed with alder than in adjacent pure conifer stands, suggesting equal or greater soil P availability under the influence of alder. We assessed the effect of low densities of red alder on soil P, using a modified Hedley sequential P fractionation scheme, in a Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) plantation in coastal Oregon. We determined that soils under plots with 190 alder stems/ha and 740 Douglas-fir stems/ha had greater inorganic P availability than pure Douglas-fir plots (740 stems/ha)...
115 citations
TL;DR: The authors related age structure and composition of forests in southeastern Pennsylvania to edaphic properties caused by the activities of a local charcoal iron furnace from the late 18th to the late 20th century.
Abstract: This study related age structure and composition of forests in southeastern Pennsylvania to edaphic properties caused by the activities of a local charcoal iron furnace from the late 18th to the la...
106 citations
TL;DR: A field experiment was established between 1989 and 1993 to study the effects of the age of clearcuts on damage by pine weevils (Hylobiusabietis L.) and competing vegetation on the survivability of cleared areas.
Abstract: A field experiment was established between 1989 and 1993 to study the effects of (i) the age of clearcuts on damage by pine weevils (Hylobiusabietis L.) and (11) competing vegetation on the survival and growth of planted Norway spruce (Piceaabies (L.) Karst.). On each of four sites Norway spruce seedlings were planted on 0 to 4-year-old clearcuts. Effects of mounding, herbicide and mowing, removal of slash, and seedling stock type were also investigated. As many seedlings suffered severely from a drought that affected southern Sweden in 1992, this study reports a separate analysis of mortality due to drough. From the middle of May until the beginning of July 1992, only negligible precipitation was recorded on all four sites. The biomass of ground vegetation was correlated with the age of the clearcut. On fresh and 1-year-old clearcuts, only negligible amounts of vegetation were found, whereas about 2 Mg•ha−1 of ground vegetation were found on 2- and 3-year-old clearcuts. Low soil water potentials were rec...
TL;DR: Six old-growth, late postfire Scots pine (Pinussylvestris L.) dominated forest stands of the Vaccinium–Cladina type were selected along a latitudinal gradient in northern Sweden and Scots pine seedlings initially establish in lichen-dominated vegetation but as they devel...
Abstract: Six old-growth, late postfire Scots pine (Pinussylvestris L.) dominated forest stands of the Vaccinium–Cladina type were selected along a latitudinal gradient in northern Sweden. In two of the stands, Scots pine seedlings that had naturally regenerated during the last 40 years were surveyed in relation to field- and bottom-layer vegetation. The most abundant forest floor species, viz. Cladina spp., occupied 41% of the ground cover and dominated the microhabitat of Scots pine seedlings 10 years), however, the cover of Cladina spp. significantly decreased and the cover of P. schreberi and various ericaceous species slightly increased. Thus Scots pine seedlings initially establish in lichen-dominated vegetation but as they devel...
TL;DR: This work reports and discusses data gathered during soil solution monitoring that was part of an experiment conducted in the Duchesnay Experimental Forest to study the effects of induced deep frost, superficial frost, and superficial frost plus drought on mature sugar maple trees.
Abstract: This work reports and discusses data gathered during soil solution monitoring that was part of an experiment conducted in the Duchesnay Experimental Forest (Quebec, Canada) to study the effects of induced deep frost, superficial frost, and superficial frost plus drought on mature sugar maple trees (Acersaccharum Marsh.). Frost treatment was applied by preventing snow from accumulating under the canopy. Soil solution chemistry was modified when mature sugar maple trees declined after exposure to a severe deep frost. The first vegetation period after treatment showed that losses of NO3− below the rooting zone were greatly increased under affected trees. The leaching rate of NO3− and basic cations was directly related to the level of change in canopy dieback and transparency. A mean NO3− concentration of 630 μmolc•L−1 (53 times the controls; max. 4500 μmolc•L−1) was measured in soil solution under the deep frost treated trees. The leaching rate of K+ (18×, relative to the control) and Mn2+ (11×) was higher t...
TL;DR: A strong correlation occurred between Δ values measured on trees in 1991 and 1992, two years that had very different precipitation and temperature conditions during the growing season, indicating that the ranking of individual trees remained almost constant between years.
Abstract: Measurements of the stable carbon isotope composition of leaf tissue were made on Piceamariana (Mill.) B.S.P trees from four full-sib families grown on three different field sites at the Petawawa N...
TL;DR: An induced defense reaction in the leaders of white spruce, Piceaglauca (Moench) Voss, occurs in response to attack by the white pine weevil.
Abstract: An induced defense reaction in the leaders of white spruce, Piceaglauca (Moench) Voss, occurs in response to attack by the white pine weevil, Pissodesstrobi Peck. The response was initiated shortly after feeding and oviposition in the attacked shoot and consisted of the cambium switching from producing normal tracheids and parenchyma ray cells to producing traumatic resin canals, arranged in a ring fashion in the developing xylem. In sectioned leaders, these traumatic resin canals could be seen emptying their contents into feeding and oviposition cavities dug by the adults, and into the larval galleries. This defense reaction killed eggs and larvae. When the leader survived the attack, the cambium reverted to producing normal xylem tissue, leaving one or more rings of traumatic resin canals embedded in the xylem annual ring.
TL;DR: In this paper, the authors measured CH4 flux from undrained, drained, and ditched portions of treed fen, forested bog and treed bog sites in the Wally Creek experimental drainage site (near Cochrane, Ontario), from May to October 1991.
Abstract: Methane (CH4) flux was measured from undrained, drained, and ditched portions of treed fen, forested bog, and treed bog sites in the Wally Creek experimental drainage site (near Cochrane, Ontario), from May to October 1991. Drainage for 7 years lowered the water table from between −21 and −49 cm to −41 and −93 cm at the three respective sites. Drainage resulted in a conversion of the peatlands from a CH4 source (0 to 15 mg CH4 •m−2 •d−1) to a small CH4 sink (0 to −0.4 mg CH4 •m−2 •d−1). In contrast, CH4 efflux from the ditches ranged from 400 mg CH4 m−2 •d−1. The flux data were used to estimate the impact of forest drainage practices on net CH4 emissions from a forest drainage complex. For the treed and forested bogs, there was a net increase in CH4 emissions where ditch spacing was closer than 38 m. Even with very close ditch spacing (>12 m), there was a net decrease in CH4 flux from the treed fen. The results of this study indicate that the combination of low antecedent CH4 fluxes from an undrain...
TL;DR: It was found that selectively logged evergreen rain forests may contain the largest long-term average stock of carbon in the biomass and products, with 207 Mg C•ha−1.
Abstract: Ten selected forest types were examined (1) to assess the carbon sequestering potential of those forest types that are most likely to be successful in sequestering atmospheric carbon, (2) to show t...
TL;DR: Although the relative importance of dominance variance in tree volume apparently declines with age, the existence of dominance Variance may warrant some changes to the current breeding strategy.
Abstract: Data from 171 full-sib tests of slash pine (Pinuselliottii Engelm. var. elliottii) measured at multiple ages between 4 and 15 years, were used to obtain restricted maximum likelihood (REML) estimates of variance components. These tests included over 2100 full-sib families, from more than 700 first-generation parents, represented by some 170 000 individuals. Analyses were completed of each test, and using standardized data, of all possible pairs of connected tests (tests with five or more common parents). Heritability, proportion of dominance variance, type B genetic correlations (which examine genotype × environment interactions), and age-age genetic correlations were estimated from the REML variance component estimates. The average heritability of volume was 0.07 at 5 years, which increased to 0.12 at 11 and 14 years of age. These heritability estimates are similar to, though slightly smaller than, previous estimates obtained from open-pollinated tests. There was approximately 1.6 times as much additive variance as dominance variance at 5 years of age, increasing to more than 2 times at 11 or more years of age. Although the relative importance of dominance variance in tree volume apparently declines with age, the existence of dominance variance may warrant some changes to the current breeding strategy. Estimates of type B genetic correlations increased from around 0.6 at 5 years to over 0.8 at 14 years, and so the importance of genotype × environment interaction appears to decline with age. These estimates of type B genetic correlations and also the estimates of age-age genetic correlations are similar to estimates from open-pollinated tests.
TL;DR: Nitrogen losses from the forest floor at the site, the Hubbard Brook Experimental Forest, New Hampshire, were lower than predictions based on previous research, and mechanical disturbance during logging may play a role in limiting short-term nitrogen losses.
Abstract: Previous research on chronosequences of even-aged northern hardwood stands has suggested that forest clearing is accompanied by large losses of nitrogen from the forest floor. The timing of the losses and the fate of a large fraction of the lost nitrogen are unclear. The purpose of this investigation was to study these questions through direct measurement of soil nitrogen concentrations and pools through time on an experimental catchment cleared in a whole-tree harvest in 1983–1984. Nitrogen losses from the forest floor at the site, the Hubbard Brook Experimental Forest, New Hampshire, were lower than predictions based on previous research. The mean forest floor nitrogen pool was 17% lower 8 years after clear-cutting of the site (P = 0.18). Predictions based on chronosequence studies suggest that 25–40% of the forest floor nitrogen would be lost after 8 years. Mechanical disturbance during logging may play a role in limiting short-term nitrogen losses. The steep midsection of the catchment experienced the...
TL;DR: Compared growth with soil and foliar elemental composition in seven stands of sugar maple in northern Vermont characterized by high or low incidence of crown dieback over the period 1989–1992, it is found that in stands with low-quality crown conditions, long-term basal area growth rates were approximately half of those in stood with higher crown quality.
Abstract: We compared growth with soil and foliar elemental composition in seven stands of sugar maple (Acersaccharum Marsh.) in northern Vermont characterized by high or low incidence of crown dieback over the period 1989–1992. In stands with low-quality crown conditions, such as elevated crown dieback, long-term basal area growth rates were approximately half of those in stands with higher crown quality. Average annual basal area growth was 17.5 cm2 for dominant trees in these stands during the period 1953–1992 compared with 32.3 cm2 for trees in higher quality stands. The occurrence of elevated crown dieback was apparently unrelated to stand characteristics such as stand age, basal area, stem density, elevation, or aspect among the stands sampled. Stands with elevated crown dieback were found on soils characterized by low pH ( <4.0), low base cation pools (particularly Ca and Mg), and higher Al in soil surface horizons than higher quality stands. Over 4 years, sugar maple stands with elevated crown dieback exhib...
TL;DR: It is concluded that dehardening during periods of warm weather may be a significant factor in freezing injury and decline of montane red spruce populations.
Abstract: We documented 3 to 14°C of dehardening in current-year foliage of 10 mature, montane red spruce (Picea rubens Sarg.) trees during a natural thaw from 12 to 21 January 1995. Mean cold tolerance was about -47°C before the onset of thaw conditions, and individuals ranged from -38 to -52OC. After 3 days of thaw, mean cold tolerance dropped to -39"C, with a range of -32 to -44°C. Trees did not regain prethaw levels of cold tolerance until sometime between 31 January and 9 February, or 10 to 20 days after subfreezing temperatures resumed. The least cold tolerant tree was at risk of injury when temperature at the field site fell to an estimated -33.8"C on 6 February, and this same tree developed noticeably more injury than other trees when injury symptoms developed in late March. No evidence of dehardening was found in balsam fir (Abies balsamea (L.) Mill.) trees from the same stand. All red spruce trees also showed the potential for net assimilation of carbon during the thaw, as determined by measurement of photosynthetic capacity under laboratory conditions. From the abrupt and substantial dehardening and persistence of the dehardened state, we conclude that dehardening during periods of warm weather may be a significant factor in freezing injury and decline of montane red spruce populations.
TL;DR: It is concluded that increasing nutrient limitation in older stands probably accounts for at least part of the decline in stand leaf area and growth.
Abstract: In southeastern Wyoming, stand leaf area and production of lodgepoie pine (Pinuscontorta Dougl.) peak early in stand development and then decline. We tested the hypothesis that these declines follo...
TL;DR: This study measured growing season soil CO2 evolution under elevated atmospheric CO2 and soil nitrogen additions to determine treatment effects, quantify seasonal variation, and determine regulating mechanisms.
Abstract: We measured growing season soil CO2 evolution under elevated atmospheric CO2 and soil nitrogen (N) additions. Our objectives were to determine treatment effects, quantify seasonal variation, and de...
TL;DR: Ringwidth chronologies from three white spruce (Piceaglauca (Moench) Voss) and two jack pine (Pinusbanksiana Lamb.) sites in the boreal forest of northern Alberta were constructed to determine whe...
Abstract: Ring-width chronologies from three white spruce (Piceaglauca (Moench) Voss) and two jack pine (Pinusbanksiana Lamb.) sites in the boreal forest of northern Alberta were constructed to determine whe...
TL;DR: Assessment of the environmental controls on FTE tree regeneration, whether the ecotone might be relictual, and whether tree invasion of nonforested FTE areas is occurring, measured tree regeneration in various environments within the FTE of Rocky Mountain National Park, Colorado.
Abstract: Ecotone vegetation may be especially sensitive to climate change. In particular, the invasion of subalpine meadows by tree seedlings has been well documented. However, there has been no systematic analysis of tree regeneration across the environmental heterogeneity of the alpine forest–tundra ecotone (FTE). Also, the position of the FTE may be relictual from more favorable climates of the past and therefore unresponsive to changing climate. To assess the environmental controls on FTE tree regeneration, to determine whether the ecotone might be relictual, and to determine whether tree invasion of nonforested FTE areas is occurring, we measured tree regeneration in various environments within the FTE of Rocky Mountain National Park, Colorado. Generally, seedling establishment appears to be controlled by patterns of soil moisture. Little seedling establishment was observed in krummholz openings, except for high seedling densities in willow wetlands. Tree seedling invasion of tundra is rare. Therefore, the up...
TL;DR: Dominant and codominant trees had a greater proportion of below-stump biomass in lateral roots, indicating that larger trees absorb a disproportionate quantity of the site's moisture and nutrients.
Abstract: Above- and below-stump biomass and nutrient content were estimated for a mature loblolly pine (Pinustaeda L.) plantation on an eroded site in the upper Piedmont of South Carolina. Pine above-stump biomass was 144.9 t•ha−1; below-stump biomass was 36.0 t•ha−1, 20% of total pine biomass. Total pine biomass was partitioned as 17% crown, 63% stem, and 20% roots. About 55% of below-stump biomass was in taproots and 45% in lateral roots. Dominant and codominant trees had a greater proportion of below-stump biomass in lateral roots, indicating that larger trees absorb a disproportionate quantity of the site's moisture and nutrients. Lateral roots contained 66 to 75% of below-stump nutrients. Fine roots (<0.6 cm diameter) accounted for 11% of below-stump biomass, but contained 24 to 30% of below-stump nutrients. Nutrient content (kg•ha−1) of above-stump biomass ranked as follows: N 164.7, Ca 154.2, K 78.0, and P 14.0. Nitrogen was also the most abundant nutrient in below-stump biomass (60.2 kg•ha−1), followed by ...
TL;DR: The relationships between site index and measures of soil, understory vegetation, and foliar nutrients were examined using data from 102 white spruce stands in the Sub-b...
Abstract: The relationships between site index and measures of soil, understory vegetation, and foliar nutrients were examined using data from 102 white spruce (Piceaglauca (Moench) Voss) stands in the Sub-b...
TL;DR: In this paper, the authors characterized the height growth and crown form of 14-year-old balsam fir regenerated naturally under a light gradient varying from 3 to 83% of photosynthetic photon flux density (PPFD).
Abstract: This study characterized the height growth and crown form of 14-year-old balsam fir regenerated naturally under a light gradient varying from 3 to 83% of photosynthetic photon flux density (PPFD). After 14 years, total height growth was correlated with percent PPFD (R2 = 0.766; p < 0.001). From 3 to 25% of PPFD, balsam firs went from a suppressed stage with an umbrella type crown shape to a full grown stage with a cone type crown shape. This morphological change was caused by a greater increase in leader length compared to the mean nodal branches length. The number of nodal and internodal branches increased with PPFD. Balsam fir crown morphology showed a strong plasticity with a light gradient going from 3 to 83% of PPFD.
TL;DR: In this paper, the use of time domain reflectometry to measure moisture content in forest soils and woody debris was evaluated and the results were developed on undisturbed soil cores from four forest stands and on...
Abstract: The use of time domain reflectometry to measure moisture content in forest soils and woody debris was evaluated. Calibrations were developed on undisturbed soil cores from four forest stands and on...
TL;DR: In this article, extensions of a basic allometric equation applied in predicting total foliage of individual trees were developed to estimate foliage and woody components of individual branches in western hemlock (Tsugaheterophylla (Raf.) Sarg.), Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco), and grand fir (Abiesgrandis (Dougl. ex D. Don) Lindl.).
Abstract: Extensions of a basic allometric equation applied in predicting total foliage of individual trees were developed to estimate foliage and woody components of individual branches in western hemlock (Tsugaheterophylla (Raf.) Sarg.), Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco), and grand fir (Abiesgrandis (Dougl. ex D. Don) Lindl.). Nine initial equations were fitted on both nonlinear and log-transformed scales to data collected in the western Cascade Mountains of Washington. In all cases, the logarithmic form of each equation provided the best fit to the data based on a modified likelihood criterion and residual patterns. Branch diameter was the overall best predictor of branch foliage and woody mass; however, significant (p = 0.05) improvements in fit were obtained when other structural and positional variables were included in the equations (e.g., foliated branch length and depth into crown). The effects of fertilization and site (locality) differences were explored using indicator variables for west...