Evaluation of planting sites common to a southeast Alaska clear-cut. I. Nutrient status

1983 ◽  
Vol 13 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Roy C. Sidle ◽  
Charles G. Shaw III

Nutrient status was evaluated in the upper 15 cm of three microsite types (rotten wood, exposed mineral soil, and undisturbed duff) common in old-growth western hemlock – Sitka spruce (Tsugaheterophylla (Raf.) Sarg.) – (Piceasitchensis (Bong.) Carr.) clear-cuts. Rotten wood had significantly wider C:N ratio (>100:1) than either undisturbed duff (36:1) or exposed mineral soil (31:1), indicating lower nitrogen availability in rotten wood. Higher levels of inorganic [Formula: see text] in <2 mm fraction of rotten wood compared with the 2- to 9.4-mm fraction indicate that N availability increases as decay advances. Available P was low and could be a major factor limiting growth in all microsites. Exchangeable Mg was relatively low (0.0025 mg/cm3) in exposed mineral soil. Microsite nutrient expression on a volumetric rather than a gravimetric basis better represents availability of nutrients to planted seedlings.

1987 ◽  
Vol 17 (4) ◽  
pp. 340-345 ◽  
Author(s):  
Roy C. Sidle ◽  
Charles G. Shaw III

Sitka spruce (Piceasitchensis (Bong.) Carr.) seedlings colonized by the ectomycorrhizal fungi Laccarialaccata (Scop. ex Fr.) Berk and Br., Hebelomacrustuliniforme (Bull, ex St. Amans) Quel., or Cenococcumgeophilum Fr. and a noninoculated control were planted on rotten wood, undisturbed duff, undisturbed duff on the north side of large stumps, and exposed mineral soil in an area recently clear-cut on Chichagof Island, southeast Alaska. Uptake and concentrations of N, P, K, Ca, Mg, and several micronutrients in foliage, stems, and roots were determined 2 years after outplanting. There were no significant interactions between fungal treatments and microsite types for uptake or concentration of any nutrient. Uptake and concentrations of N and P in foliage and roots did not differ significantly among fungal treatments. Foliar K and Cu concentrations were significantly higher in control seedlings than in those with L. laccata ectomycorrhizae. Calcium was the only nutrient analyzed that was present in higher concentrations in seedlings inoculated with H. crustuliniforme than in controls. Concentrations of foliar P, Mn, and Zn were significantly greater in seedlings grown on undisturbed duff (protected north side) than in seedlings grown on exposed mineral soil. However, foliar concentrations of all nutrients tested were not significantly different between seedlings grown on undisturbed duff (unprotected sites) and those grown on mineral soil. Seedlings grown on rotten wood had significantly greater concentrations of foliar Ca than seedlings grown on either exposed mineral soil or undisturbed duff. The on-site colonization of control seedlings after outplanting indicates that resident ectomycorrhizal fungi readily establish and appear to provide equal if not improved nutrient benefits compared to inoculated seedlings. Greater nutritional benefits were derived by planting on certain microsite types (duff and protected duff) than by inoculating with specific ectomycorrhizal fungi.


1983 ◽  
Vol 13 (1) ◽  
pp. 9-11 ◽  
Author(s):  
Charles G. Shaw III ◽  
Roy C. Sidle

Three microsites common to clear-cuts logged by the high-lead method in southeast Alaska were sampled to quantify the occurrence and viability of sclerotia of Cenococcumgeophilum Fr. Undisturbed duff had significantly greater numbers of sclerotia per gram or per cubic centimetre of soil than either exposed mineral soil or rotten wood. There were significantly fewer viable sclerotia per cubic centimetre of rotten wood than in either exposed mineral soil or undisturbed duff. Numbers of viable sclerotia that could contact the root plug of a containerized seedling when it was planted into rotten wood, exposed mineral soil, or undisturbed duff were calculated to be 0.7, 6.1, and 7.2, respectively. Expressing abundance of mycorrhizal propagules by soil volume, rather than weight, is more meaningful when microsites with large differences in soil bulk density are compared.


1989 ◽  
Vol 19 (2) ◽  
pp. 185-191 ◽  
Author(s):  
Stephen C. Hart ◽  
Mary K. Firestone

Three indices of nitrogen (N) availability were compared in the field over a 1-year period in an old-growth and a young-growth mixed-conifer forest. The indices utilized were ion exchange resin (IER) bags, buried bags, and a core-IER method employing intact soil cores enclosed in tubes capped at both ends by IER bags. The results from all three methods indicated that in the surface mineral soil, N availability was higher in the young-growth stand than in the old-growth stand. However, seasonal patterns of N availability were generally not well correlated among the methods (correlation coefficients ranged from 0.32 to 0.62). For a given amount of net N mineralized in buried bags, more N accumulated on IER bags placed in the young-growth stand than in those placed in the old-growth stand. This was the result of greater net nitrification in the young-growth stand coupled with the greater mobility of [Formula: see text] relative to [Formula: see text] in soil. Ten-month estimates of net N mineralization measured by the core-IER and buried-bag methods were similar in the young-growth stand (about 42 mg•kg soil−1), but the core-IER estimate was almost twice that of the buried-bag estimate in the old-growth stand (31.7 and 16.8 mg•kg soil−1, respectively). The different sensitivities of the core-IER and buried-bag methods to changes in soil moisture and leaching probably account for much of the difference in their N availability estimates. Results from the core-IER method did reflect the effects of leaching; however, soil water content within the core did not follow changes in soil water content effectively. Because of the greater labor involved in using the core-IER method, its use may be most efficacious in high-precipitation environments, or when in-field soil incubations must be conducted for extended periods of time.


1987 ◽  
Vol 17 (4) ◽  
pp. 334-339 ◽  
Author(s):  
Charles G. Shaw III ◽  
Roy C. Sidle ◽  
Arland S. Harris

Hebelomacrustuliniforme (Bull. ex St. Amans) Quel., Laccarialaccata (Scoop. ex Fr.) Berk and Br., and Cenococcumgeophilum (L. ex Fr.) Pers. ex Hooker were established as ectomycorrhizae on container-grown Sitka spruce seedlings. These seedlings and noninoculated controls were planted in rotten wood, exposed mineral soil, undisturbed duff, and undisturbed duff on the north side of large stumps on one clear-cut site in southeast Alaska. At planting, seedling heights differed significantly among fungal treatments: the tallest were those inoculated with C. geophilum, the shortest with H. crustuliniforme. Some height differences persisted after planting, but 3-year height and diameter increments did not differ significantly among fungal treatments and controls. As a percentage of their initial height, seedlings inoculated with L. laccata increased the least in size after 3 years (70%), significantly less than for seedlings with H. crustuliniforme (126%). All test fungi survived for 2 years, but most seedlings were further colonized by one or more on-site ectomycorrhizal fungi, frequently C. geophilum. Regardless of fungal treatment, seedlings in rotten wood had the least percentage increase in height after 3 years (69%), significantly less than the 121% increase for seedlings in undisturbed duff on the north side of stumps. Seedling survival after 3 years was over 92% and did not differ by microsite or fungal treatment. At another clear-cut site, survival of noninoculated seedlings after 3 years was 86% in exposed mineral soil, significantly less than the 98% on all other microsites. Frost heave was the primary cause of mortality. These data suggest that prior colonization by these ectomycorrhizal fungi provides little survival or growth benefit after out planting Sitka spruce seedlings on various microsites in southeast Alaskan clear-cuts. Some improvement in early height growth and survival may be obtained, however, by planting in undisturbed duff, particularly near stumps, and by avoiding exposed mineral soil.


1987 ◽  
Vol 17 (12) ◽  
pp. 1585-1595 ◽  
Author(s):  
Phillip Sollins ◽  
Steven P. Cline ◽  
Thomas Verhoeven ◽  
Donald Sachs ◽  
Gody Spycher

Fallen boles (logs) of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco), western hemlock (Tsugaheterophylla (Raf.) Sarg.), and western red cedar (Thujaplicata Donn) in old-growth stands of the Cascade Range of western Oregon and Washington were compared with regard to their physical structure, chemistry, and levels of microbial activity. Western hemlock and western red cedar logs disappeared faster than Douglas-fir logs, although decay rate constants based on density change alone were 0.010/year for Douglas-fir, 0.016/year for western hemlock, and 0.009/year for western red cedar. We were unable to locate hemlock or red cedar logs older than 100 years on the ground, but found Douglas-fir logs that had persisted up to nearly 200 years. Wood density decreased to about 0.15 g/cm3 after 60–80 years on the ground, depending on species, then remained nearly constant. Moisture content of logs increased during the first 80 years on the ground, then remained roughly constant at about 250% (dry-weight basis) in summer and at 350% in winter. After logs had lain on the ground for about 80 years, amounts of N, P, and Mg per unit volume exceeded the amount present initially. Amounts of Ca, K, and Na remained fairly constant throughout the 200-year time span that was studied (100-year time span for Na). N:P ratios converged toward 20, irrespective of tree species or wood tissue type. C:N ratios dropped to about 100 in the most decayed logs; net N was mineralized during anaerobic incubation of most samples with a C:N ratio below 250. The ratio of mineralized N to total N increased with advancing decay. Asymbiotic bacteria in fallen logs fixed about 1 kg N ha−1 year−1, a substantial amount relative to system N input from precipitation and dry deposition (2–3 kg ha−1 year−1).


2021 ◽  
Author(s):  
Guiyao Zhou ◽  
César Terrer ◽  
Bruce Hungate ◽  
Natasja van Gestel ◽  
Xuhui Zhou ◽  
...  

Abstract Plants may slow global warming through enhanced growth, because increased levels of photosynthesis stimulate the land carbon (C) sink. However, the key drivers determining responses of plants to warming remain unclear, causing uncertainty in climate projections. Using meta- analysis, we show that the effect of experimental warming on plant biomass is best explained by soil nitrogen (N) availability. Warming-induced changes in total, aboveground and belowground biomass all positively correlated with soil C:N ratio, an indicator of soil N availability. In factorial N × warming experiments, warming increased plant biomass more strongly under low N than under high N availability. Together, these results suggest that warming stimulates plant C storage most strongly in ecosystems where N limits plant growth. Thus, incorporating the soil N status of ecosystems into Earth system models may improve predictions of future carbon-climate feedbacks.


1989 ◽  
Vol 46 (8) ◽  
pp. 1383-1391 ◽  
Author(s):  
John F. Thedinga ◽  
Michael L. Murphy ◽  
Jonathan Heifetz ◽  
K V. Koski ◽  
Scott W. Johnson

Short-term effects of logging on age composition and size of juvenile coho salmon (Oncorhynchus kisutch) were studied in 18 streams in Southeast Alaska in 1982 and 1983; studies were in old-growth and clear-cut reaches with or without buffer strips. The number of fry (age 0) in summer and winter was proportionately higher in buffered and clear-cut reaches than in old-growth reaches, and all treatments averaged a 20% decrease in fry from summer to winter. Fry length and condition factor were greater for buffered and clear-cut reaches than for old-growth reaches, whereas parr (age 1 and older) size did not differ among treatments. Fry and parr were larger in the southern than in the northern regions and their length and weight were directly related to peripbyton biomass and benthos density. A higher percentage of large [Formula: see text] fry remained in buffered reaches than in clear-cut and old-growth reaches; therefore, the density of fry that were potentially large enough to become smolts the next spring (presmolts) was greater in buffered reaches. The larger fry in buffered and clear-cut reaches compared with old-growth reaches was probably due to earlier fry emergence that resulted from increased water temperature.


2011 ◽  
Vol 41 (1) ◽  
pp. 195-210 ◽  
Author(s):  
Alison Cross ◽  
Steven S. Perakis

Old-growth forests of the Pacific Northwest provide a unique opportunity to examine tree species – soil relationships in ecosystems that have developed without significant human disturbance. We characterized foliage, forest floor, and mineral soil nutrients associated with four canopy tree species (Douglas-fir (Pseudotsuga menziesii (Mirbel) Franco), western hemlock (Tsuga heterophylla (Raf.) Sarg.), western redcedar (Thuja plicata Donn ex D. Don), and bigleaf maple (Acer macrophyllum Pursh)) in eight old-growth forests of the Oregon Coast Range. The greatest forest floor accumulations of C, N, P, Ca, Mg, and K occurred under Douglas-fir, primarily due to greater forest floor mass. In mineral soil, western hemlock exhibited significantly lower Ca concentration and sum of cations (Ca + Mg + K) than bigleaf maple, with intermediate values for Douglas-fir and western redcedar. Bigleaf maple explained most species-based differences in foliar nutrients, displaying high concentrations of N, P, Ca, Mg, and K. Foliar P and N:P variations largely reflected soil P variation across sites. The four tree species that we examined exhibited a number of individualistic effects on soil nutrient levels that contribute to biogeochemical heterogeneity in these ecosystems. Where fire suppression and long-term succession favor dominance by highly shade-tolerant western hemlock, our results suggest a potential for declines in both soil Ca availability and soil biogeochemical heterogeneity in old-growth forests.


2021 ◽  
Author(s):  
Guiyao Zhou ◽  
César Terrer ◽  
Bruce Hungate ◽  
Natasja van Gestel ◽  
Xuhui Zhou ◽  
...  

Abstract Plants may slow global warming through enhanced growth, thereby stimulating the land carbon (C) sink. However, the key drivers determining responses of plants to warming remain unclear, causing uncertainty in climate projections. Using meta-analysis, we show that the effect of experimental warming on plant biomass is best explained by soil C:N ratio, an indicator of soil nitrogen (N) availability. Our results suggest that warming stimulates plant C storage most strongly in ecosystems where N limits plant growth, and may inform model predictions of warming may improve by considering spatially explicitly .


1982 ◽  
Vol 12 (2) ◽  
pp. 343-353 ◽  
Author(s):  
M. Meyer Schoenberger ◽  
D. A. Perry

In a greenhouse bioassay of soils from the central Oregon Cascades, Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) seedlings had the most total and ectomycorrhizal root tips when grown in soil from an unburned clear-cut and the least when grown in soil from (i) a 20-year-old plantation that had been clear-cut and burned in the late 1950's and (ii) one old-growth forest. Tip formation was intermediate in soil from a second old-growth forest, a recently burned clear-cut, and a 40-year-old natural burn. Root weights followed the same trend, but top weights did not differ among the various soils. Ectomycorrhizal and total root tips of western hemlock (Tsugaheterophylla (Raf.) Sarg.) were lowest in soils from the plantation and recently burned clear-cut. Unlike Douglas-fir, western hemlock's tip production was not greater in the unburned clear-cut than in the old-growth forest soils. In this species, both top and root weights varied according to soil, with the largest seedlings produced in soil from the unburned clear-cut. With both species, there was a significant interaction between ectomycorrhizal type and soil type. Cenococcumgeophilum Fr. predominated on western hemlock and was reduced in soils from the burned clear-cut and plantation. In comparison with the mean for all soils, ectomycorrhizal types that predominated on Douglas-fir were enhanced in the unburned clear-cut soil and reduced in one old-growth soil, an effect apparently related to litter leachate.


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