Nutrient cycling following whole-tree and conventional harvest in northern mixed forest

1989 ◽  
Vol 19 (6) ◽  
pp. 725-735 ◽  
Author(s):  
O. Q. Hendrickson ◽  
L. Chatarpaul ◽  
D. Burgess

Soil and water chemistry and soil-respiration activity were studied in a mature, mixed conifer and hardwood forest and in adjacent whole-tree harvest (WTH) and conventional harvest (CH) areas dominated by hardwood sprouts. Compared with the uncut mature forest, forest floor contents of N and K were lower in the WTH area 3 years after harvest; Ca and Mg were higher in the CH area, probably owing to inputs in logging slash. Mineral soil Ca and pH were higher in the harvested areas than in the uncut area. During the 2nd year after harvest, cation concentrations in forest floor leachate varied in the order WTH > CH > uncut area, but differences largely disappeared the next year. Soil water NO3 concentrations were slightly elevated in the CH area, but only 1.6 kg N•ha−1•year−1 leached below the rooting zone. Bulk precipitation K and Mg concentrations were lower in the WTH area than in the CH area owing to the loss of canopy leaching from the residual stand. Slightly higher amounts of cations were found in the snowpack under the mature forest canopy. Midwinter rains caused movement of NO3 and H within the snowpack. Despite the higher soil-respiration rates in the harvested areas, no differences in soil organic matter pools were observed relative to the uncut area; harvest-related inputs of slash, decaying roots, and stumps may have offset respiratory carbon losses. Current high nutrient demands of rapidly growing sprouts in the WTH area greatly exceed nutrient inputs in bulk precipitation; this may lead to future growth declines.


1998 ◽  
Vol 78 (1) ◽  
pp. 35-44 ◽  
Author(s):  
Mark Johnston ◽  
Julie Elliott

The Boreal Mixedwood Ecosystem Study near Thunder Bay, Ontario is a multi-disciplinary investigation of the impacts of harvesting and fire on the structure and function of a boreal mixed-wood ecosystem. The fire component comprises a set of treatments in which fire severity was manipulated by adjusting fuel loadings through a variety of harvesting techniques, and also included fire in standing timber. Intensive fuel sampling before and after the fire enabled detailed determinations of fuel consumption, heat output and forest floor reduction. Nutrient concentrations in ash, soil, and plant tissue following the fire were compared with fire severity in order to quantify potential nutrient inputs and their relationship to the amount of biomass consumed during the fire. Forest floor and woody fuel consumption varied significantly among treatments, with the most important factor being whether or not the stand had been harvested previous to the fire. The pH was highest and P concentrations among the lowest in the ash of unharvested blocks. Nutrient concentrations of the remaining forest floor and upper mineral soil were weakly related to the treatments. Forest floor P concentrations were highest on whole-tree harvested and lowest on uncut blocks. Whole-tree harvested blocks also had the highest pH values in forest floor and mineral soil. Concentrations of N, P, and Mg in the foliage of Populus tremuloides Michx. and Rubus idaeus L. were higher on unharvested burned than cut and burned plots, and were negatively correlated with the depth of forest floor reduction. These results indicate that fire severity plays a role in determining the extent of nutrient enrichment following fire, and may be important in influencing long-term site productivity. Key words: Fire severity, forest fire, nutrient cycles, soil chemistry, fire ecology



2008 ◽  
Vol 54 (No. 8) ◽  
pp. 377-387
Author(s):  
P. Sah S ◽  
R. Brumme ◽  
N. Lamersdorf

We analysed stable isotopes of N in a spruce forest under ambient rainfall (no further manipulation of the atmospheric input) and clean rain application (10 years of reduced inorganic N- and acid-constituent input). The objectives of the study were to assess whether or not the natural <sup>15</sup>N abundance would function as an indicator for the N-status of our forest ecosystems. For this purpose, natural <sup>15</sup>N abundance values were measured in needles, litter fall, roots, soil, bulk precipitation, throughfall and soil water of both plots. In the bulk precipitation and throughfall the &delta;<sup>15</sup>N values of NO<sub>3</sub>-N were in the range reported by other studies (–16 to + 23‰). In both plots, the throughfall was greatly depleted of <sup>15</sup>N compared to the bulk precipitation and this was attributed to nitrification in the canopy leaves, leading to &delta;<sup>15</sup>N-depleted nitrate production in the leaves that leaches down the soil surface. Nitrate in seepage water showed a general increase in &delta;<sup>15</sup>N values when it passes through the upper mineral soil (10 cm soil depth) and infiltrates into deeper mineral soil horizons (100 cm soil depth), similar to the &delta;<sup>15</sup>N enrichment of total nitrogen in the mineral soil. We observed <sup>15</sup>N depletion in both green needles and litter fall at the clean rain plot, compared to the N-saturated control plot. We assumed it to be due to increased mycorrhizal N-uptake under N limited, i.e. clean rain conditions which are indicated by relatively lower N concentrations of green needles. With respect to the vertical gradient of the <sup>15</sup>N abundance in the forest floor, both plots differ from each other, showing an untypical peak of &delta;<sup>15</sup>N depletion in the humus layer, which is more pronounced at the control plot. In contrast to the mineral soil where mineralisation is a dominant process for fractionation we attribute the &delta;<sup>15</sup>N pattern in the forest floor to additional processes like litter input and immobilisation. We conclude that the &delta;<sup>15</sup>N natural abundance analysis is helpful for interpreting the N-status of forest ecosystems but further research is needed especially with respect to the soil-root interface.



1984 ◽  
Vol 14 (6) ◽  
pp. 763-767 ◽  
Author(s):  
C. Anthony Federer

Organic content of the forest floor decreases for several years after clear-cutting, and then slowly recovers. Thickness, bulk density, organic matter, and nitrogen content of forest floors were measured for 13 northern hardwood stands in the White Mountains of New Hampshire. Stands ranged from 1 to about 100 years in age. Forest-floor thickness varied significantly with stand age, but bulk density, organic fraction, and nitrogen fraction were independent of age. Total organic content of the forest floor agreed very well with data from Covington's (W. W. Covington 1981. Ecology, 62: 41–48) study of the same area. Both studies indicated that mature forest floors have about 80 Mg organic matter•ha−1 and 1.9 Mg nitrogen•ha−1. Within 10 or 15 years after cutting, the organic matter content of the floor decreases to 50 Mg•ha−1, and its nitrogen content to 1.1 Mg•ha−1. The question whether the decrease is rapid and the minimum broad and flat, or if the decrease is gradual and the minimum sharp, cannot be answered. The subsequent increase to levels reached in mature forest requires about 50 years. Some of the initial decrease in organic matter and nitrogen content of the forest floor may be caused by organic decomposition and nitrogen leaching, but mechanical and chemical mixing of floor into mineral soil, during and after the harvest operation, may also be important. The difference is vital with respect to maintenance of long-term productivity.



2000 ◽  
Vol 80 (3) ◽  
pp. 507-514 ◽  
Author(s):  
Sylvain St-Laurent ◽  
Rock Ouimet ◽  
Sylvie Tremblay ◽  
Louis Archambault

Following the Rio and Kyoto protocols, forest sequestration of organic C (Corg) appears to be among the measures to reduce atmospheric C. In this context, we assessed the evolution of soils' reserves of Corg after complete whole-tree forest harvesting in the balsam fir–yellow birch forest of eastern Quebec. The experimental design consisted of eight plots in mature stands, and 10 plots in 7-, 12-, and 22-yr-old clearcuts in the "Seigneurie du Lac Métis", located 80 km south-east of Rimouski, Quebec, Canada. The soil type was an Orthic Humo-ferric Podzol. Major Corg losses occured in the forest floor of the 7-, 12- and 22-yr-old harvested plots compared with mature stands. The FH horizon of harvested plots showed a loss of 44% (−30.5 t ha−1) in dry weight and 13.5% (−62.1 g kg–1) in Corg content between 7 and 22-yr-old harvested plots. More than half the Corg content of the forest floor was lost in that time (−52% or −16.6 t ha−1). The Corg stock of the L horizon were lowered only for the 7-yr-old treatment (2.5 t ha−1) compared with mature stands (4.9 t ha−1). No significant differences in the Corg stocked in the first 30 m of the mineral soil were found between treatments. It appears that the forest floor of balsam fir–yellow birch stands has become a source of Corg for at least 22 yr after forest harvesting. Key words: Forest harvesting, soil, organic carbon, forest floor



1986 ◽  
Vol 16 (4) ◽  
pp. 872-874 ◽  
Author(s):  
O. Q. Hendrickson

Three years after harvesting a mixed conifer–hardwood forest in Ontario, the density of sweet fern (Comptoniaperegrina (L.) Coult.) was far greater on a whole-tree harvest site (logging slash removed) than on an adjacent conventional harvest site (logging slash present). These differences were related to the degree of site disturbance, particularly forest floor removal. Nodule fixation rates also appeared to reflect the degree of disturbance, being highest in plants growing along a logging road where the sandy, nitrogen-poor mineral soil was exposed, and exceptionally low on the conventional harvest site (0.67 μmol C2H4 g dry weight−1 h−1). Overall, acetylene reduction activity showed a significant negative correlation (r = −0.77, p < 0.001) with total N.



Forests ◽  
2017 ◽  
Vol 9 (1) ◽  
pp. 16 ◽  
Author(s):  
Matthew Powers ◽  
Randall Kolka ◽  
John Bradford ◽  
Brian Palik ◽  
Martin Jurgensen


2008 ◽  
Vol 38 (4) ◽  
pp. 647-655 ◽  
Author(s):  
S. Singh ◽  
B. D. Amiro ◽  
S. A. Quideau

Soil respiration and its spatial and temporal variation were studied at three boreal forest sites in central Saskatchewan, Canada, burned in 1998, 1989, and 1977. Soil respiration, soil temperature, and organic layer thickness were measured at 100 points in a grid pattern of 2 m × 2 m at each site in 2004 and 2005. The mean within-site spatial coefficient of variation was 35%, and the measurements were not spatially autocorrelated. We found no significant difference in variance between the two youngest sites (P > 0.05), whereas the older site showed significantly lower variance (P < 0.05). Soil respiration was not correlated with the forest floor organic layer thickness at any of the sites (R2 < 0.1). Removal of the forest floor layer reduced the soil respiration by 17% to 38%, depending on the site. Thus, the respiration from the mineral soil seemed to contribute a major fraction of the total soil respiration (62%–83%). Soil respiration was positively linearly related to the fine root biomass (R2 = 0.63–0.85, P < 0.05) at all sites. We conclude that variation in root biomass has a larger effect than differential forest floor organic layers on variation in soil respiration in young boreal postfire forests.



2019 ◽  
Author(s):  
Jörg Matschullat ◽  
Roberval Monteiro Bezerra de Lima ◽  
Sophie F. von Fromm ◽  
Solveig Pospiech ◽  
Andrea M. Ramos ◽  
...  

Abstract. Given the dimensions of the Amazon basin (7.5 million km2), its internal dynamics, increasing anthropogenic strain on this large biome, and its global role as one of two continental biospheric tipping elements, it appears crucial to have data-based knowledge on carbon and nitrogen concentrations and pools as well as on possible intra-annual dynamics. We quantified carbon (Ct, Corg), nitrogen (N) and sulfur (S) concentrations in litter (ORG) and mineral soil material (TOP 0–20 cm, BOT 30–50 cm) of upland (terra firme) oxisols across Amazonas state and present a first pool calculation. Data are based on triplicate seasonal sampling at 29 sites (forest and post-forest) within the binational project EcoRespira-Amazon (ERA). Repeated sampling increased data accuracy and allows for interpreting intra-annual (seasonal) and climate-change related dynamics. Extreme conditions between the dry season in 2016 and the subsequent wet season (ENSO-related) show differences more clearly. Median CNS in the Amazon basin TOP soils (Ct 1.9, Corg 1.6, N 0.15, S 0.03 wt-% under forest canopy) as well as Corg / N ratios show concentrations similar to European soils (FOREGS, GEMAS). TOP Ct concentrations ranged from 1.02 to 3.29 wt-% (medianForest 2.17 wt-%; medianPost-Forest 1.75 wt-%), N from 0.088 to 0.233 wt-% (medianForest 0.17 wt-%; medianPost-Forest 0.09 wt-%) and S from 0.012 to 0.051 wt.-% (medianForest 0.03 wt.-%; medianPost-Forest 0.02 wt-%). Corg / N ratios ranged from 6 to 14 (median 10). A first pool calculation (hectare-based) illustrates forest versus post-forest changes. The elements are unevenly distributed in the basin with generally higher CNS values in the central part (Amazonas graben) as compared to the southern part of the basin. Deforestation and drought conditions lead to C and N losses – within 50 years after deforestation, C and N losses average 10 to 15 %. Regional climate change with increased drought will likely speed up carbon and nitrogen losses.



2002 ◽  
Vol 32 (2) ◽  
pp. 344-352 ◽  
Author(s):  
P W Clinton ◽  
R B Allen ◽  
M R Davis

Stemwood production, N pools, and N availability were determined in even-aged (10, 25, 120, and >150-year-old) stands of a monospecific mountain beech (Nothofagus solandri var. cliffortioides (Hook. f.) Poole) forest in New Zealand recovering from catastrophic canopy disturbance brought about by windthrow. Nitrogen was redistributed among stemwood biomass, coarse woody debris (CWD), the forest floor, and mineral soil following disturbance. The quantity of N in stemwood biomass increased from less than 1 kg/ha in seedling stands (10 years old) to ca. 500 kg/ha in pole stands (120 years old), but decreased in mature stands (>150 years old). In contrast, the quantity of N stored in CWD declined rapidly with stand development. Although the mass of N stored in the forest floor was greatest in the pole stands and least in the mature stands, N availability in the forest floor did not vary greatly with stand development. The mass of N in the mineral soil (0–100 mm depth) was also similar for all stands. Foliar N concentrations, net N mineralization, and mineralizable N in the mineral soil (0–100 mm depth) showed similar patterns with stage of stand development, and indicated that N availability was greater in sapling (25 years old) and mature stands than in seedling and pole stands. We conclude that declining productivity in older stands is associated more with reductions in cation availability, especially calcium, than N availability.



Forests ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1427
Author(s):  
Chunju Cai ◽  
Zhihan Yang ◽  
Liang Liu ◽  
Yunsen Lai ◽  
Junjie Lei ◽  
...  

Nitrogen (N) deposition has been well documented to cause substantial impacts on ecosystem carbon cycling. However, the majority studies of stimulating N deposition by direct N addition to forest floor have neglected some key ecological processes in forest canopy (e.g., N retention and absorption) and might not fully represent realistic atmospheric N deposition and its effects on ecosystem carbon cycling. In this study, we stimulated both canopy and understory N deposition (50 and 100 kg N ha−1 year−1) with a local atmospheric NHx:NOy ratio of 2.08:1, aiming to assess whether canopy and understory N deposition had similar effects on soil respiration (RS) and net ecosystem production (NEP) in Moso bamboo forests. Results showed that RS, soil autotrophic (RA), and heterotrophic respiration (RH) were 2971 ± 597, 1472 ± 579, and 1499 ± 56 g CO2 m−2 year−1 for sites without N deposition (CN0), respectively. Canopy and understory N deposition did not significantly affect RS, RA, and RH, and the effects of canopy and understory N deposition on these soil fluxes were similar. NEP was 1940 ± 826 g CO2 m−2 year−1 for CN0, which was a carbon sink, indicating that Moso bamboo forest the potential to play an important role alleviating global climate change. Meanwhile, the effects of canopy and understory N deposition on NEP were similar. These findings did not support the previous predictions postulating that understory N deposition would overestimate the effects of N deposition on carbon cycling. However, due to the limitation of short duration of N deposition, an increase in the duration of N deposition manipulation is urgent and essential to enhance our understanding of the role of canopy processes in ecosystem carbon fluxes in the future.



Sign in / Sign up

Export Citation Format

Share Document