Timber harvest and frequent prescribed burning interact to affect the demography of Eucalypt species

Forest management, fire, and herbivores are the major factors affecting regeneration of deciduous trees in boreal forests. In a large-scale experiment, we manipulated the use of prescribed burning, the level of green-tree retention and the presence of moose ( Alces alces L.) and hare ( Lepus timidus L. and Lepus europaeus Pallas) to study their effects on early regeneration of three native pioneer tree species, i.e., rowan ( Sorbus aucuparia L.), aspen ( Populus tremula L.), and silver birch ( Betula pendula Roth). Green-tree retention enhanced survival of all tested tree species. Prescribed burning enhanced the survival rate of birch and rowan, but aspen survival was only enhanced by burning on clearcuts and areas with 50 m3/ha of retention trees. Excluding moose enhanced rowan growth and birch survival. Aspen growth and survival was enhanced when both moose and hare were excluded. Seedlings were most frequently browsed on clearcuts, and most seedling mortality was caused by voles or hare. At low densities, the effect of moose on pioneer trees may be smaller than that of other herbivores or the fire–management regime. Considering the large number of species depending on pioneer trees, the results support the use of tree retention and fire as useful management alternatives not only to promote biodiversity but also to enhance regeneration of deciduous trees and reduce herbivore damage.

Download Full-text

Phytosociological changes in understory vegetation following timber harvest in northern Minnesota

Canadian Journal of Forest Research ◽

10.1139/x81-023 ◽

1981 ◽

Vol 11 (1) ◽

pp. 175-183 ◽

Cited By ~ 21

Author(s):

Kenneth Wayne Outcalt ◽

Edwin H. White

Keyword(s):

Prescribed Burning ◽

Woody Species ◽

Timber Harvest ◽

Burned Area ◽

Growing Seasons ◽

Core Species ◽

Resource Managers ◽

Paper Birch ◽

Tree Length ◽

Major Factors

Impacts on the understory of a balsam fir (Abiesbalsamea (L.) Mill.) – paper birch (Betuiapapyrifera Marsh.) stand, caused by winter and spring full-tree logging and by winter tree-length logging which was followed by summer burning, were monitored for two growing seasons after overstory harvest. New species invaded full-tree logging sites, while compositional changes on the burned area were due primarily to the disappearance of species. Prescribed burning on the tree-length logging area prevented the quick increase in density of woody species that occurred on full-tree harvested sites. However, understory production increased on all sites, and by the end of the second season aboveground biomass was 3847, 4516, and 2604 kg/ha on the winter full-tree, spring full-tree, and winter tree-length plus burning sites, respectively, compared with 942 kg/ha on the uncut control.The major factors causing differences were prescribed burning and snow cover during harvest operations. Since our results concur with previous findings and appear predictable, resource managers can choose the technique best suited to specific objectives. However, no matter which system is used, the same core species will persist afterward, and if succession is allowed to continue, an understory will develop similar to that existing before harvest.

Download Full-text

Understory biomass and nutrients 2 years after timber harvest in northern Minnesota

Canadian Journal of Forest Research ◽

10.1139/x81-041 ◽

1981 ◽

Vol 11 (2) ◽

pp. 306-309 ◽

Cited By ~ 5

Author(s):

Kenneth W. Outcalt ◽

Edwin H. White

Keyword(s):

Prescribed Burning ◽

Woody Species ◽

Timber Harvest ◽

Control Site ◽

Clear Cut ◽

Available Nutrients ◽

Tree Length ◽

Understory Biomass ◽

Whole Tree

Adjacent areas within a 60-year-old Abiesbalsamea (L.) Mill. – Betulapapyrifera Marsh, stand in northern Minnesota, U.S.A., were clear-cut by whole-tree logging or tree-length logging followed by prescribed burning. Two years after harvest, understory biomass and nutrients were sampled on these sites and on an adjoining uncut control. All logged sites had significantly more total aboveground understory biomass than the control. However, biomass of woody species on the tree-length logged burn area did not differ from the control site. Because of the greater biomass on harvested sites, nutrient accumulations (N, P, K, Ca, Mg) by the understory were greater, with about 75% of these extra nutrients in herbs and shrubs. Although the quantity of nutrients in the understory is less than that removed with the overstory, it is important in maintaining the nutritional integrity of the system because it serves as a sink for available nutrients.

Download Full-text

Effects of green tree retention and prescribed burning on the crown damage caused by the pine shoot beetles (Tomicus spp.) in pine-dominated timber harvest areas

Journal of Applied Entomology ◽

10.1111/j.1439-0418.2005.01015.x ◽

2006 ◽

Vol 130 (1) ◽

pp. 37-44 ◽

Cited By ~ 16

Author(s):

P. Martikainen ◽

J. Kouki ◽

O. Heikkala ◽

E. Hyvarinen ◽

H. Lappalainen

Keyword(s):

Prescribed Burning ◽

Timber Harvest ◽

Tree Retention ◽

Green Tree Retention ◽

Pine Shoot Beetles

Download Full-text

Modeling Smoldering Emissions From Prescribed Broadcast Burns in the Pacific-Northwest

International Journal of Wildland Fire ◽

10.1071/wf9940135 ◽

1994 ◽

Vol 4 (3) ◽

pp. 135 ◽

Cited By ~ 4

Author(s):

SA Ferguson ◽

CC Hardy

Keyword(s):

Pacific Northwest ◽

Exponential Decay ◽

Prescribed Burning ◽

Field Measurements ◽

Timber Harvest ◽

Production Model ◽

Total Biomass ◽

Fuel Loading ◽

Pollution Impacts ◽

Improved Model

The objective of this study was to improve a smoke emissions model that is currently being used to help reduce pollution impacts from prescribed burning of timber harvest residues. Smoke emissions from these types of burns have been characterized with in situ, real time sampling packages. When emissions flux data from these sampling packages were compared with an existing emissions production model, it was found that the variety of rate characteristics for smoldering combustion caused by different burning conditions were not adequately described by the model. Therefore, we used the acquired data to develop an improved model for the early smoldering portion of broadcast prescribed fires. First, the data were compared with field measurements of pre-burn fuel loading, fuel moisture, and calculated biomass consumption. A linear relation was found between total biomass consumption and a rate constant for the exponential decay of smoldering emissions. The resulting regression equation was compared with observed data from previous studies and found to adequately predict an exponential decay constant, which is used to describe the early smoldering portion of harvest residue burns.

Download Full-text