The emergence of forest age structures as determined by uneven-aged stands and age class forests

2016 ◽  
Vol 25 ◽  
pp. 160-179
Author(s):  
Renke Coordes
Keyword(s):  
Forest Age ◽  
Age Class ◽  
Age Structures

Timber production versus old-growth preservation with endogenous prices and forest age-classes

2004 ◽  
Vol 34 (6) ◽  
pp. 1296-1310 ◽  
Author(s):  
Olli Tahvonen
Keyword(s):  
Environmental Values ◽  
Timber Harvesting ◽  
Timber Production ◽  
Forest Age ◽  
Forest Land ◽  
Age Classes ◽  
Old Growth ◽  
Class Distribution ◽  
Age Class ◽  
Long Run

This study combines timber production and environmental values, applying a dynamic forest-level economic model with any number of forest age-classes. The model includes endogenous timber price or nonlinear harvesting costs and various possibilities to specify the dependence of environmental values (related e.g. to species persistence) on the forest age-class structure. The nonlinearities in the net benefits from timber production have the consequence that fluctuations in optimal timber harvesting may totally vanish or at least become smaller than in forest scheduling models without ad hoc even flow constraints. If environmental values are specified to depend on the fraction of forest land preserved as old growth, the optimal long run allocation between timber production and old growth is represented by an equilibrium continuum. Thus the optimal long run allocation depends on the initial age-class distribution. The continuum and the dependence of initial age-class distribution vanish when the rate of discount approaches zero. If the environmental values of age-classes increase smoothly with age, the long run equilibrium may simultaneously include multiple rotation periods. The model determines the optimality of producing timber and environmental values separately at different parts of the forest or at the same piece of forest land. Numerical computation suggests that the optimal solution always converges toward some optimal long run stationary age-class distribution.

Forest age class structures as indicators of sustainability in boreal forest: Are we measuring them correctly?

2012 ◽  
Vol 23 ◽  
pp. 202-210 ◽  
Author(s):  
Jérome Garet ◽  
Frédéric Raulier ◽  
David Pothier ◽  
Steve G. Cumming
Keyword(s):  
Boreal Forest ◽  
Forest Age ◽  
Age Class

scholarly journals Projections of future forest age class structure under the influence of fire and harvesting: implications for forest management in the boreal forest of eastern Canada

2017 ◽  
Vol 90 (4) ◽  
pp. 485-495 ◽  
Author(s):  
Yves Bergeron ◽  
Dinesh Babu Irulappa Pillai Vijayakumar ◽  
Hakim Ouzennou ◽  
Frédéric Raulier ◽  
Alain Leduc ◽  
...  
Keyword(s):  
Forest Management ◽  
Boreal Forest ◽  
Class Structure ◽  
Forest Age ◽  
Eastern Canada ◽  
Age Class

Using salvage logging and tolerance to risk to reduce the impact of forest fires on timber supply calculations

2015 ◽  
Vol 45 (4) ◽  
pp. 480-486 ◽  
Author(s):  
A. Leduc ◽  
P.Y. Bernier ◽  
N. Mansuy ◽  
F. Raulier ◽  
S. Gauthier ◽  
...  
Keyword(s):  
Forest Fires ◽  
Timber Harvest ◽  
Mitigation Measures ◽  
Class Structure ◽  
Forest Age ◽  
Timber Supply ◽  
Salvage Logging ◽  
Age Class ◽  
Burn Rate ◽  
The Impact

It is acknowledged that natural forest fires cannot and even should not be eliminated from the North American boreal forest. Forest fires produce immediate losses of wood volume, disrupt the conversion of the actual forest age structure into a target structure, and prevent planned timber supply (PTS) levels from being achieved. In this paper, we explore the extent to which periodic shortfalls in available timber under various burn rates can be mitigated through salvage logging and the tolerance of forest managers to a given level of shortfall, both as a function of forest age class structure. Simulations are done using both a deterministic and a stochastic representation of burn rate over time. Results show that the frequency of shortfall events can be reduced by salvage logging and by the introduction of measures that generate a tolerance to shortfall and that this mitigation potential is influenced by initial forest age class structure and burn rate. Results also show that even a 100% rate of salvage logging cannot fully compensate for timber losses to fire and eliminate fire-induced timber shortfalls. Furthermore, interannual burn rate variability reduces the efficiency of both mitigation measures. As the PTS is never realized under fire risk, the real cost of opting for different PTS scenarios should be estimated not from the difference in PTS but rather from the more realistic difference in realized timber harvest.

scholarly journals Accounting for forest age in the tile-based dynamic global vegetation model JSBACH4 (4.20p7; git feature/forests) – a land surface model for the ICON-ESM

2019 ◽  
Author(s):  
Julia E. M. S. Nabel ◽  
Kim Naudts ◽  
Julia Pongratz
Keyword(s):  
Forest Management ◽  
Land Surface ◽  
Gross Primary Production ◽  
Surface Model ◽  
Forest Age ◽  
Age Classes ◽  
Dynamic Global Vegetation Model ◽  
Area Index ◽  
Global Vegetation ◽  
Age Structures

Abstract. Natural and anthropogenic disturbances, in particular forest management, affect forest age-structures all around the globe. Forest age-structures in turn influence biophysical and biogeochemical interactions of the vegetation with the atmosphere. Yet, many dynamic global vegetation models (DGVMs), including those used as land surface models (LSMs) in Earth system models (ESMs), do not account for subgrid forest age structures, despite being used to investigate land-use effects on the global carbon budget or simulating land–atmosphere interactions. In this paper we present a new scheme to introduce forest age-classes in hierarchical tile-based DGVMs combining benefits of recently applied approaches. Our scheme combines a computationally efficient age-dependent simulation of all relevant processes, such as photosynthesis and respiration, without loosing the information about the exact forest age, which is a prerequisite for the implementation of age-based forest management. This combination is achieved by using the hierarchy to track the area fraction for each age on an aggregated plant functional type level, whilst simulating the relevant processes for a set of age-classes. We describe how we implemented this scheme in JSBACH4, the LSM of the ICON-ESM. Subsequently, we compare simulation output against global observation-based products for gross primary production, leaf area index and above-ground biomass to assess the ability of simulations with and without age-classes to reproduce the annual cycle and large-scale spatial patterns of these variables. The comparisons show differences exponentially decreasing with the number of distinguished age-classes and linearly increasing computation costs. The results demonstrate the benefit of the introduction of age-classes, with the optimal number of age-classes being a compromise between computation costs and accuracy.

scholarly journals Fire History of the Lamar River Drainage Yellowstone National Park

1990 ◽  
Vol 14 ◽  
pp. 131-133
Author(s):  
Stephen Barrett ◽  
Stephen Arno
Keyword(s):  
Data Base ◽  
Fire History ◽  
Lodgepole Pine ◽  
Whitebark Pine ◽  
Forest Age ◽  
Subalpine Fir ◽  
River Drainage ◽  
Age Class ◽  
Gis Data ◽  
History Of

In this paper we discuss the first phase of a 3-year effort to document the fire history of Yellowstone National Park's (YNP) Lamar River drainage southeast of Soda Butte Creek. The overall goal of the study was to provide managers with a more complete understanding of YNP natural fire regimes. Specific objectives were: 1. Determine natural (pre-1900) fire periodicities, severities, burning patterns, and post-fire succession within the study area's major forest types (Douglas fir/ grassland, lodgepole pine/subalpine fir/ spruce, whitebark pine/lodgepole pine/ subalpine fir, and whitebark pine/subalpine fir timberline habitats); 2. document and map the pre-1988 forest age-class mosaic; and 3. digitize the age-class mosaic map for the YNP's GIS data base. This study is considered especially timely because the 1988 fires destroyed much evidence of area fire history. Our sampling in 1989 focused on a 24,000 ha area encompassing the Cache Creek drainage, which was severely burned in 1988. The forest age-class mosaic was sampled by increment boring and sawing fire scar samples from old trees (Arno and Sneck 1977, Barrett and Arno 1988). Aerial photographs were used to map the pre-1988 forest age-class mosaic; Data was digitized for the park's GIS data base. Information from the YNP fire atlas also was useful in interpreting fire patterns during the post-1900 period.

scholarly journals STUDY ON MONGOLIAN FOREST STAND DYNAMICS USING MATHEMATICAL MODELING

2017 ◽  
pp. 13-25
Author(s):  
Khulan M ◽  
Liu Junchang
Keyword(s):  
Forest Fire ◽  
Age Structure ◽  
Forest Stand ◽  
Stand Dynamics ◽  
Forest Age ◽  
Forest Resource ◽  
Forested Area ◽  
Age Class ◽  
Commercial Logging ◽  
Main Factors

A Global warming, climate change and negative human activities are expected to directly and negatively influence Mongolia’s forest resource area and quality [21]. In 2015, Mongolian forested area was 12,188.2 thousand hectare and in compared with the forested area in 2010, it has decreased by 864.5 thousand hectare. The important causes of deforestation and forest degradation are fire, improper commercial logging, illegal collection of wood for construction and fuel wood, overgrazing, mining activity, and damage by pests and diseases. Mongolian forest stand is not only decreasing in quantity, but also forest age class has been changing into maturity forest classification in recent years. The maturity forest resource has counted for 74 percent of total forest resource is in National Forest Inventory, 2016. There are few study for Mongolian forest stand dynamics and this work is first research that used stochastic process to predict forest stand dynamics in Mongolian case. This paper considered the main factors such as Climate factors and Socio-Economic factors in predicting forest stand dynamics. The factors are chosen based on real situation of forest resource’s changes in Mongolia. The study has estimated coefficients of relationship between forest resource and main factors, as well as main factors and their explanatory variables, using suitable regression model for all estimation. Moreover, Markov chain process has been used to extracted future dynamic of forest stand by age class structure based on imbalanced age structure of total forest resource today. The result of this paper shows that the most important factors that influenced the future forest stand changes are forest fire, commercial logging and afforestation. The estimated model results shows the forest fire will be decreased (9%), commercial logging will be increased (25%) and reforestation will be increased (30%) by 2030. Specially, this paper presented that forest resource will be decreased by 13 percent in future 15 years. Additionally, this decrease is consist of forest age structure changes which is young aged forest would be increased by 27%, middle aged forest would be decreased by 15%, maturing forest would be decreased by 39% and maturity forest would be decreased by 16% in 2030.

The Missing Tail and Other Considerations for the Use of Fire History Models

1995 ◽  
Vol 5 (4) ◽  
pp. 197 ◽  
Author(s):  
MA Finney
Keyword(s):  
Exponential Distribution ◽  
Exponential Model ◽  
Forest Age ◽  
Age Classes ◽  
Class Distribution ◽  
Age Class ◽  
Negative Exponential Distribution ◽  
Negative Exponential Model ◽  
Negative Exponential ◽  
Tests Of Fit

This paper reviews methods used for testing the fit of the cumulative form of a negative exponential distribution to the cumulative distribution of forest age-classes. It is shown that existing methods can lead to a greater chance of falsely rejecting the fit of the negative exponential model and inferring that fire frequencies have changed through time. This results when the old-age tail of a negative exponential distribution is mathematically assumed to be present at the end of the age-class distribution. In reality, the tail is censored from sample distributions of forest age-classes. Censoring alters the shape of a cumulative age-class distribution from the straight line expected for a semi-log graph of the cumulative negative exponential model. A solution to this problem is proposed that restricts the tests-of-fit to the portion of the negative exponential distribution that overlaps with the data to be tested. The cumulative age-class distribution can then be compared directly with the cumulative of a truncated negative exponential distribution. Considerations for interpreting a poor fit are then discussed.

scholarly journals Accounting for forest age in the tile-based dynamic global vegetation model JSBACH4 (4.20p7; git feature/forests) – a land surface model for the ICON-ESM

2020 ◽  
Vol 13 (1) ◽  
pp. 185-200 ◽  
Author(s):  
Julia E. M. S. Nabel ◽  
Kim Naudts ◽  
Julia Pongratz
Keyword(s):  
Forest Management ◽  
Land Surface ◽  
Surface Model ◽  
Earth System ◽  
Forest Age ◽  
Age Classes ◽  
Dynamic Global Vegetation Model ◽  
Area Index ◽  
Global Vegetation ◽  
Age Structures

Abstract. Natural and anthropogenic disturbances, in particular forest management, affect forest age structures all around the globe. Forest age structures in turn influence key land surface processes, such as photosynthesis and thus the carbon cycle. Yet, many dynamic global vegetation models (DGVMs), including those used as land surface models (LSMs) in Earth system models (ESMs), do not account for subgrid forest age structures, despite being used to investigate land-use effects on the global carbon budget or simulating biogeochemical responses to climate change. In this paper we present a new scheme to introduce forest age classes in hierarchical tile-based DGVMs combining benefits of recently applied approaches the first being a computationally efficient age-dependent simulation of all relevant processes, such as photosynthesis and respiration, using a restricted number of age classes and the second being the tracking of the exact forest age, which is a prerequisite for any implementation of age-based forest management. This combination is achieved by using the tile hierarchy to track the area fraction for each age on an aggregated plant functional type level, whilst simulating the relevant processes for a set of age classes. We describe how we implemented this scheme in JSBACH4, the LSM of the ICOsahedral Non-hydrostatic Earth system model (ICON-ESM). Subsequently, we compare simulation output to global observation-based products for gross primary production, leaf area index, and above-ground biomass to assess the ability of simulations with and without age classes to reproduce the annual cycle and large-scale spatial patterns of these variables. The comparisons show decreasing differences and increasing computation costs with an increasing number of distinguished age classes. The results demonstrate the benefit of the introduction of age classes, with the optimal number of age classes being a compromise between computation costs and error reduction.

Lodgepole pine forest age class dynamics and susceptibility to mountain pine beetle attack

2005 ◽  
Vol 2 (3) ◽  
pp. 232-239 ◽  
Author(s):  
Chao Li ◽  
Hugh J. Barclay ◽  
Brad C. Hawkes ◽  
S.W. Taylor
Keyword(s):  
Mountain Pine Beetle ◽  
Lodgepole Pine ◽  
Pine Forest ◽  
Forest Age ◽  
Age Class ◽  
Mountain Pine ◽  
Pine Beetle
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