Predicting the effects of different harvesting regimes on productivity and yield in northern hardwoods

1979 ◽  
Vol 9 (1) ◽  
pp. 10-14 ◽  
Author(s):  
John D. Aber ◽  
Danield B. Botkin ◽  
Jerry M. Melillo
Keyword(s):  
Nitrogen Availability ◽  
Total Yield ◽  
Forest Growth ◽  
Northern Hardwoods ◽  
Net Production ◽  
Clear Cutting ◽  
Litter Input ◽  
Forest Growth Model ◽  
Whole Tree ◽  
Forest Cutting

Projected levels of nitrogen availability resulting from seven different harvesting regimes in northern hardwoods were used as inputs to a forest growth model. Results were analysed in terms of differences in net production and total yield by treatment. Production was highest under long (90-year) rotations and was reduced under short (45- and 30-year) rotations. Intensive harvesting (whole tree and complete forest cutting) removed a greater percentage of net production than clear-cutting. Complete forest utilization on a 90-year rotation produced the greatest total yield assuming that all harvesting treatments had the same effect on rates of regeneration and successional changes in litter input to the forest floor.

scholarly journals White spruce understory protection: From planning to growth and yield

2014 ◽  
Vol 90 (01) ◽  
pp. 35-43 ◽  
Author(s):  
Brigitte E. Grover ◽  
Mike Bokalo ◽  
Ken J. Greenway
Keyword(s):  
Growth Model ◽  
Total Yield ◽  
Light Availability ◽  
White Spruce ◽  
Forest Growth ◽  
Growth And Yield ◽  
Light Levels ◽  
Forest Growth Model ◽  
Supply Analysis ◽  
The Impact

A large component of the boreal mixedwood forest is comprised of aspen and white spruce mixtures of varying proportions and ages. The slower growing white spruce usually starts as an understory component but will succeed to a white sprucedominated stand after aspen break-up. Since both species are utilized by the forest industry, one method of maximizing total yield is to protect the unmerchantable white spruce understory while harvesting the merchantable aspen overstory. Although some of the white spruce understory is lost when the machine corridors are harvested, future conifer yield is augmented by the accelerated growth of the protected spruce component, a result of increased light levels. In a 10 year trial comparing the growth of released versus control understory spruce, annual height growth, diameter growth and volume increment were 76%, 152% and 83% higher, respectively, for the released conifer compared to the control. In order to account for the yield implications in timber supply analysis, accurate forecasts of future stand development can only be obtained through the use of a forest growth model since long-term data are not available. The Mixedwood Growth Model (MGM) has a unique architecture that allows for the modeling of various strata in understory protection stands. This “multi-strata” modeling approach was used to forecast the combined yield of all the strata, including the impact of adjacent strata with regards to light availability. Operational examples of understory protection, data on white spruce release and aspen regeneration, as well as modeled volume forecasts are presented.

Predicting the effects of different harvesting regimes on forest floor dynamics in northern hardwoods

1978 ◽  
Vol 8 (3) ◽  
pp. 306-315 ◽  
Author(s):  
John D. Aber ◽  
Daniel B. Botkin ◽  
Jerry M. Melillo
Keyword(s):  
Organic Matter ◽  
Forest Management ◽  
Computer Model ◽  
Forest Floor ◽  
Nitrogen Availability ◽  
Forest Harvesting ◽  
Northern Hardwoods ◽  
Clear Cutting ◽  
Short Rotation ◽  
Harvesting Intensity

The effects of different intensities of forest management on forest floor organic matter and nitrogen dynamics in northern hardwoods were simulated with a computer model built from the extensive data base of the Hubbard Brook Ecosystem Study. Three cutting intensities and three rotation lengths were tested. In all cases, both nitrogen availability and forest floor organic matter declined for 15–30 years following cutting and required 60–80 years to recover to precut levels. Rotation length had a much greater effect on the forest floor than harvesting intensity with short-rotation (30-year) complete forest harvesting causing the greatest reduction in both biomass and nitrogen availability. Average forest floor biomass under this treatment was reduced to roughly one-half of that under clear-cutting (90-year rotation).

Das nachhaltig verfügbare Holznutzungspotenzial im Schweizer Wald

2016 ◽  
Vol 167 (3) ◽  
pp. 162-171 ◽  
Author(s):  
Ruedi Taverna ◽  
Michael Gautschi ◽  
Peter Hofer
Keyword(s):  
National Level ◽  
Reference Value ◽  
Forest Growth ◽  
Long Term Effects ◽  
Management Scenarios ◽  
Additional Time ◽  
Basic Scenario ◽  
Economic Framework ◽  
Forest Growth Model ◽  
New Findings

The sustainably available wood use potential in Swiss forests Based on the most recent simulations created using the Massimo forest growth model, the sustainably available wood use potential in Swiss forests was calculated for five management scenarios for the next three decades as well as for two additional time periods in the future (to monitor the long-term effects). The term “sustainably available wood use potential” covers those wood quantities that could be put on the market, taking into account socio-ecological and economic restrictions on use. The sustainably available wood use potential is provided for production regions, priority functions as well as the assortment and qualities of timber. The previously used factors of the applied “onion” model were checked and modified, if necessary, in order to take new findings and current cost developments into consideration. The calculations for all scenarios come up with a sustainably available wood use potential that is much lower than in earlier investigations. Depending on the scenario and decade, sustainably available wood use potential accounts for less than 50% of the total use potential. The biggest decrease in total use potential was due to economic framework conditions. Turning to Switzerland as a whole, towards the end of the investigation period (2106) those scenarios including a sharp increase in use in the first three decades result in a sustainably available wood use potential that is clearly lower than the reference value used at the beginning of the simulation. In the basic scenario (constant stock) and in the scenario in which the form of management used to date (increasing stock) was simulated, the sustainably available wood use potential at national level remained more or less the same throughout the simulation period, ranging from 5 to 6 million m3 per year.

scholarly journals Model-Based Estimation of Amazonian Forests Recovery Time after Drought and Fire Events

Forests ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 8
Author(s):  
Bruno L. De Faria ◽  
Gina Marano ◽  
Camille Piponiot ◽  
Carlos A. Silva ◽  
Vinícius de L. Dantas ◽  
...  
Keyword(s):  
Recovery Time ◽  
Regional Scale ◽  
Forest Growth ◽  
Forest Recovery ◽  
Fire Intensity ◽  
Natural Ecosystems ◽  
Spatial And Temporal Patterns ◽  
Southeastern Part ◽  
Forest Growth Model ◽  
Carbon Losses

In recent decades, droughts, deforestation and wildfires have become recurring phenomena that have heavily affected both human activities and natural ecosystems in Amazonia. The time needed for an ecosystem to recover from carbon losses is a crucial metric to evaluate disturbance impacts on forests. However, little is known about the impacts of these disturbances, alone and synergistically, on forest recovery time and the resulting spatiotemporal patterns at the regional scale. In this study, we combined the 3-PG forest growth model, remote sensing and field derived equations, to map the Amazonia-wide (3 km of spatial resolution) impact and recovery time of aboveground biomass (AGB) after drought, fire and a combination of logging and fire. Our results indicate that AGB decreases by 4%, 19% and 46% in forests affected by drought, fire and logging + fire, respectively, with an average AGB recovery time of 27 years for drought, 44 years for burned and 63 years for logged + burned areas and with maximum values reaching 184 years in areas of high fire intensity. Our findings provide two major insights in the spatial and temporal patterns of drought and wildfire in the Amazon: (1) the recovery time of the forests takes longer in the southeastern part of the basin, and, (2) as droughts and wildfires become more frequent—since the intervals between the disturbances are getting shorter than the rate of forest regeneration—the long lasting damage they cause potentially results in a permanent and increasing carbon losses from these fragile ecosystems.

scholarly journals Improved understanding of drought controls on seasonal variation in Mediterranean forest canopy CO<sub>2</sub> and water fluxes through combined in situ measurements and ecosystem modelling

2009 ◽  
Vol 6 (8) ◽  
pp. 1423-1444 ◽  
Author(s):  
T. Keenan ◽  
R. García ◽  
A. D. Friend ◽  
S. Zaehle ◽  
C. Gracia ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Forest Canopy ◽  
Moisture Stress ◽  
Mediterranean Ecosystems ◽  
Forest Growth ◽  
Water Fluxes ◽  
Soil Moisture Stress ◽  
Dynamic Global Vegetation Model ◽  
Forest Growth Model

Abstract. Water stress is a defining characteristic of Mediterranean ecosystems, and is likely to become more severe in the coming decades. Simulation models are key tools for making predictions, but our current understanding of how soil moisture controls ecosystem functioning is not sufficient to adequately constrain parameterisations. Canopy-scale flux data from four forest ecosystems with Mediterranean-type climates were used in order to analyse the physiological controls on carbon and water flues through the year. Significant non-stomatal limitations on photosynthesis were detected, along with lesser changes in the conductance-assimilation relationship. New model parameterisations were derived and implemented in two contrasting modelling approaches. The effectiveness of two models, one a dynamic global vegetation model ("ORCHIDEE"), and the other a forest growth model particularly developed for Mediterranean simulations ("GOTILWA+"), was assessed and modelled canopy responses to seasonal changes in soil moisture were analysed in comparison with in situ flux measurements. In contrast to commonly held assumptions, we find that changing the ratio of conductance to assimilation under natural, seasonally-developing, soil moisture stress is not sufficient to reproduce forest canopy CO2 and water fluxes. However, accurate predictions of both CO2 and water fluxes under all soil moisture levels encountered in the field are obtained if photosynthetic capacity is assumed to vary with soil moisture. This new parameterisation has important consequences for simulated responses of carbon and water fluxes to seasonal soil moisture stress, and should greatly improve our ability to anticipate future impacts of climate changes on the functioning of ecosystems in Mediterranean-type climates.

Tree growth and drought impact the dynamics of C allocation and change the coupling between photosynthesis and respiration in stem and soil

2021 ◽  
Author(s):  
Yu Tang ◽  
Pauliina Schiestl-Aalto ◽  
Kira Ryhti ◽  
Liisa Kulmala ◽  
Elina Sahlstedt ◽  
...  
Keyword(s):  
Climate Change ◽  
Growing Season ◽  
Forest Growth ◽  
Time Lags ◽  
Dry Period ◽  
Organ Growth ◽  
Substrate Concentrations ◽  
Photosynthesis And Respiration ◽  
Whole Tree ◽  
Tree Organ

&lt;p&gt;In-depth knowledge about carbon (C) flows within trees and from the trees to forest ecosystem via respiration is essential for accurate modeling of tree growth and C balance. However, significant gaps still exist in our understanding about how trees allocate C for growth and respiration of different tree organs, which makes it difficult to predict the response of forest growth to climate change. A powerful tool to study C allocation within trees is stable C isotope ratio (the ratio of &lt;sup&gt;13&lt;/sup&gt;C to &lt;sup&gt;12&lt;/sup&gt;C relative to a reference, noted as &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C), as this signal is passed from C sources to C sinks with isotopic fractionation along the pathway. In this study, we monitored the &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C signal of CO&lt;sub&gt;2&lt;/sub&gt; fluxes of shoot (A&lt;sub&gt;canopy&lt;/sub&gt;), stem (R&lt;sub&gt;stem&lt;/sub&gt;) and soil (R&lt;sub&gt;soil&lt;/sub&gt;) in a Scots pine (Pinus sylvestris L.) dominated boreal forest in southern Finland for summer 2018, which included a month-long dry period. We also traced the growth of current-year shoots, needles, stem, and fine roots (fibrous and pioneer roots) and the concentrations and &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C of putative substrates (sugars and starch) in phloem and roots of Scots pine over the growing season. We calculated the correlations between substrate concentrations and respiration fluxes, as well as the correlations between &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C of A&lt;sub&gt;canopy&lt;/sub&gt; and &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C of R&lt;sub&gt;soil&lt;/sub&gt; or &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C of R&lt;sub&gt;stem&lt;/sub&gt; with varying time lags from 3 d to 14 d for different tree organ growth periods and the dry period. We found tight couplings between photosynthesis and respiration, when newly assimilated sugars were allocated to stem or roots for growth or for drought response. These couplings include: 1) a synchrony between fibrous root growth and the concentrations of bulk sugars and starch in roots, associated with increases in R&lt;sub&gt;soil&lt;/sub&gt; under high root substrate concentrations; 2) promoted nighttime R&lt;sub&gt;stem&lt;/sub&gt; under high substrate supply to stem, which is seen as increased phloem glucose to sucrose ratio; 3) shorter time lags between &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C of A&lt;sub&gt;canopy&lt;/sub&gt; and &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C of R&lt;sub&gt;stem&lt;/sub&gt; under higher stem growth demands; 4) shorter time lags between &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C of A&lt;sub&gt;canopy&lt;/sub&gt; and &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C of R&lt;sub&gt;soil&lt;/sub&gt; under drought stress than with no water stress. The time lags between &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C of A&lt;sub&gt;canopy&lt;/sub&gt; and &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C of R&lt;sub&gt;soil&lt;/sub&gt; or &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C of R&lt;sub&gt;stem&lt;/sub&gt; being not uniform further implies that tree C allocation patterns are dynamic over the growing season. In addition, the C allocation to stem and roots occurred after full expansion of current-year shoots or needles, reflecting a whole tree C allocation strategy for growth demands of different tree organs, which prioritizes the demands of source organs. We suggest that the dynamics of C allocation in response to tree organ growth and drought stress should be considered in whole tree C allocation models for projecting forest growth under climate change.&lt;/p&gt;

scholarly journals Evaluation of the Agronomic Performance of Organic Processing Tomato as Affected by Different Cover Crop Residues Management

Agronomy ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 504 ◽  
Author(s):  
Abou Chehade ◽  
Antichi ◽  
Martelloni ◽  
Frasconi ◽  
Sbrana ◽  
...  
Keyword(s):  
Plant Growth ◽  
Cover Crop ◽  
Nitrogen Availability ◽  
Crop Residues ◽  
N Uptake ◽  
Total Yield ◽  
Soluble Solids ◽  
Plastic Mulch ◽  
Processing Tomato ◽  
No Till

No-till practices reduce soil erosion, conserve soil organic carbon, and enhance soil fertility. Yet, many factors could limit their adoption in organic farming. The present study investigated the effects of tillage and cover cropping on weed biomass, plant growth, yield, and fruit quality of an organic processing tomato (Solanum lycopersicon L. var. Elba F1) over two seasons (2015–2017). We compared systems where processing tomato was transplanted on i) tilled soil following or not a winter cover crop (Trifolium squarrosum L.) and with/without a biodegradable plastic mulch; and ii) no-till where clover was used, after rolling and flaming, as dead mulch. Tomato in no-till suffered from high weed competition and low soil nitrogen availability leading to lower plant growth, N uptake, and yield components with respect to tilled systems. The total yield in no-till declined to 6.8 and 18.3 t ha−1 in 2016 and 2017, respectively, with at least a 65% decrease compared to tilled clover-based systems. No evidence of growth-limiting soil compaction was noticed but a slightly higher soil resistance was in the no-till topsoil. Tillage and cover crop residues did not significantly change tomato quality (pH, total soluble solids, firmness). The incorporation of clover as green manure was generally more advantageous over no-till. This was partly due to the low performance of the cover crop where improvement may limit the obstacles (i.e., N supply and weed infestation) and enable the implementation of no-till in organic vegetable systems.

Development and Use of Bounding Functions in a Forest Growth Model

1993 ◽  
Vol 8 (1) ◽  
pp. 24-27
Author(s):  
K. Leroy Dolph ◽  
Gary E. Dixon
Keyword(s):  
Computer Simulation ◽  
Simulation Models ◽  
Height Growth ◽  
Forest Growth ◽  
Growth And Yield ◽  
Forest Growth Model ◽  
Individual Trees ◽  
Computer Simulation Models ◽  
Forest Growth And Yield

Abstract Erroneous predictions of forest growth and yield may result when computer simulation models use extrapolated data in repeated or long-term projections or if the models are used outside the range of data on which they were built. Bounding functions that limit the predicted diameter and height growth of individual trees to maximum observed values were developed to constrain these erroneous predictions in a forest growth and yield simulator. Similar techniques could be useful for dealing with extrapolated data in other types of simulation models. West. J. Appl. For. 8(1):24-27.

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