Tree mortality and forest structure in the temperate rain forests of southeast Alaska

2003 ◽  
Vol 33 (9) ◽  
pp. 1621-1634 ◽  
Author(s):  
Paul E Hennon ◽  
Michael H McClellan
Keyword(s):  
Tree Mortality ◽  
Stand Structure ◽  
Woody Debris ◽  
Basal Area ◽  
Structural Diversity ◽  
Small Scale ◽  
Southeast Alaska ◽  
Dead Trees ◽  
Fall Direction ◽  
High Degree

Tree mortality in 27 old-growth stands at three locales in southeast Alaska was evaluated to determine how types of tree death contributed to stand structure and the production of woody debris and to interpret small-scale disturbance. Basal area, density of stems, and the condition of dead trees were described for each tree species. Dead trees with broken boles were observed most frequently, followed by dead standing intact and uprooted trees. The frequencies of dead trees within snag and log deterioration classes indicated that most trees died standing and subsequently broke. Reconstructed annual mortality rates for overstory trees averaged 0.3–0.5%·year–1 for the three locales and were relatively stable through the previous century. Tree fall direction for both uprooted and broken trees aligned significantly with the downslope direction. All three types of tree mortality contributed substantially to structural diversity, reflecting a high degree of complexity associated with small-scale disturbance at these three study locales.

Stand dynamics of mixed red alder – conifer forests of southeast Alaska

2004 ◽  
Vol 34 (4) ◽  
pp. 969-980 ◽  
Author(s):  
Robert L Deal ◽  
Paul E Hennon ◽  
Ewa H Orlikowska ◽  
David V D'Amore
Keyword(s):  
Stand Structure ◽  
Large Diameter ◽  
Basal Area ◽  
Height Growth ◽  
Diameter Distribution ◽  
Height Distribution ◽  
Conifer Forests ◽  
Red Alder ◽  
Southeast Alaska ◽  
Dead Trees

Stand structure and dynamics were evaluated in mixed red alder (Alnus rubra Bong.) – conifer forests of southeast Alaska. We assessed stand development, tree density, total basal area, diameter distribution of live and dead trees, height distribution of live trees, and mean diameter of all and largest conifers in 40-year-old red alder – conifer stands that developed following logging. Forty-five plots were established in nine stands sampled across a com po si tional range of 0%–86% alder. Alder height growth was initially rapid then slowed considerably, whereas conifer height growth was initially slow then rapidly increased with conifers now being 4–9 m taller than associated alders. Most alder diameters were 20–30 cm and conifer diameters were more variable with numerous small (3–10 cm) and a few large (>25 cm) trees. Total stand basal area significantly decreased (p = 0.013) with increasing proportions of alder, but density of live and dead trees was not closely associated with alder composition. More than 60% of all dead trees died standing regardless of size or species. Overall, these mixed red alder – conifer stands provided more heterogeneous structures than pure conifer stands, with more even diameter distributions, multiple canopy layers, and similar numbers of large diameter conifers.

scholarly journals Resources of dead wood in the municipal forests in Warsaw

2015 ◽  
Vol 76 (4) ◽  
pp. 322-330 ◽  
Author(s):  
Konrad Skwarek ◽  
Szymon Bijak
Keyword(s):  
National Parks ◽  
Coarse Woody Debris ◽  
Forest Ecosystems ◽  
Dead Wood ◽  
Woody Debris ◽  
Forest Site ◽  
Natural Forests ◽  
Dead Trees ◽  
Standing Dead ◽  
High Degree

Abstract Dead wood plays an important role for the biodiversity of forest ecosystems and influences their proper development. This study assessed the amount of coarse woody debris in municipal forests in Warsaw (central Poland). Based on the forest site type, dominant tree species and age class, we stratified all complexes of the Warsaw urban forests in order to allocate 55 sample plots. For these plots, we determined the volume of dead wood including standing dead trees, coarse woody debris and broken branches as well as uprooted trees. We calculated the amount of dead wood in the distinguished site-species-age layers and for individual complexes. The volume of dead matter in municipal forests in Warsaw amounted to 38,761 m3, i.e. 13.7 m3/ha. The obtained results correspond to the current regulations concerning the amount of dead organic matter to be left in forests. Only in the Las Bielański complex (northern Warsaw) volume of dead wood is comparable to the level observed in Polish national parks or nature reserves, which is still far lower than the values found for natural forests. In general, municipal forests in Warsaw stand out positively in terms of dead wood quantity and a high degree of variation in the forms and dimensions of dead wood.

scholarly journals Rocky pine forests in the High Coast Region in Sweden: structure, dynamics and history

2020 ◽  
Vol 38 ◽  
pp. 101-130
Author(s):  
Jennie Sandström ◽  
Mattias Edman ◽  
Bengt Gunnar Jonsson
Keyword(s):  
Human Impact ◽  
Fire History ◽  
Dead Wood ◽  
Forest Type ◽  
Basal Area ◽  
Pine Forests ◽  
Small Scale ◽  
Natural Dynamics ◽  
Almost All ◽  
High Degree

Almost all forests in Sweden are managed and only a small fraction are considered natural. One exception is low productive forests where, due to their limited economical value, natural dynamics still dominate. One example is the Scots pine (Pinus sylvestris L.) forests occurring on rocky and nutrient-poor hilltops. Although these forests represent a regionally common forest type with a high degree of naturalness, their dynamics, structure and history are poorly known. We investigated the structure, human impact and fire history in eight rocky pine forests in the High Coast Area in eastern Sweden, initially identified as good representatives of this forest type. This was done by sampling and measuring tree sizes, -ages, fire-scarred trees, as well as dead wood volumes and quality along three transects at each site. The structure was diverse with a sparse layer of trees (basal area 9 m2 and 640 trees larger than 10 cm ha-1) in various sizes and ages; 13 trees ha-1 were more than 300 years old. Dead wood (DW), snags and logs in all stages of decay, was present and although the actual DW (pine) volume (4.4 m3 ha-1) and number of units (53 ha-1) was low, the DW share of total wood volume was 18% on average. Dead wood can be present for several centuries after death; we found examples of both snags and logs that had been dead more than 300 years. Frequent fires have occurred, with an average cycle of 40 years between fires. Most fires occurred between 1500-1900 and many of them (13) during the 1600s. However, fires were probably small since most fire years were only represented at one site and often only in one or a few samples. The rocky pine forests in the High Coast Area are representative of undisturbed forests with low human impact, exhibiting old-growth characteristics and are valuable habitats for organisms connected to sun-exposed DW. Management of protected rocky pine forests may well include small-scale restoration fires and the limited DW volumes should be protected.

scholarly journals Tree mortality in the dynamics and management of uneven-aged Norway spruce stands in southern Finland

2020 ◽  
Vol 139 (6) ◽  
pp. 989-998
Author(s):  
Sauli Valkonen ◽  
Lucie Aulus Giacosa ◽  
Juha Heikkinen
Keyword(s):  
Tree Mortality ◽  
Stand Structure ◽  
Basal Area ◽  
Repeated Measurements ◽  
Common Causes ◽  
Single Tree Selection ◽  
Spruce Stands ◽  
Causes Of Mortality ◽  
Number Of Stems ◽  
Adverse Influence

Abstract This study focused on tree mortality in spruce-dominated stands managed using the single-tree selection method in southern Finland. Together with regeneration and tree growth, mortality is one of the basic elements of the stand structure and dynamics in selection stands. The study was based on data acquired from a set of 20 permanent experimental plots monitored with repeated measurements for 20 years. The average mortality in the number of stems (N) was 4.45 trees ha−1a−1, in basal area (G) 0.07 m2 ha−1a−1, and in stemwood volume (V) 0.56 m3 ha−1a−1. In relative terms it was 0.50% of N, 0.30% of G and 0.27% of V, respectively. Wind and snow were the most common causes of mortality, while deaths by biotic causes (mammals, insects, pathogens) were extremely rare. Some 6–10% of the total loss in the number of stems and volume was attributable to the loss or removal of trees that sustained serious damage in harvesting. Most of the mortality occurred in the smallest diameter classes of up to 20 cm. Such a high mortality among small trees can have an adverse influence on the sustainability of selection structures if not successfully checked in harvesting and management.

scholarly journals Effects of Oak Decline on Species Composition in a Northern Arkansas Forest

2003 ◽  
Vol 27 (4) ◽  
pp. 264-268 ◽  
Author(s):  
Eric Heitzman
Keyword(s):  
Species Composition ◽  
Tree Mortality ◽  
Stand Structure ◽  
Acer Rubrum ◽  
Basal Area ◽  
Red Oak ◽  
Oak Decline ◽  
Northern Red Oak ◽  
Red Maple ◽  
White Oak

Abstract Since 1999, widespread and locally severe oak decline and mortality have occurred throughout the Ozark Mountains of northern Arkansas and southern Missouri. A contributing factor in the decline and mortality is an outbreak of the red oak borer [Enaphalodes rufulus (Haldeman) (Coleoptera: Cerambycidae)]. In northern Arkansas, a 2,150 ac mature oak forest severely affected by decline was selected as a case study to describe changes in species composition and stand structure and to assess regeneration potential of oaks and non-oak species. Mortality reduced total overstory basal area from 105 to 57 ft2/ac, and overstory density decreased from 156 to 89 trees/ac. Most dead and dying trees were northern red oak (Quercus rubra L.) and black oak (Q. velutina Lam.). Basal area and density of overstory red oaks were reduced from 51 to 11 ft2/ac and from 60 to 11 trees/ac, respectively. These trees died regardless of dbh class. Mortality was less common in white oak (Q. alba L.) and was generally limited to smaller trees. Understory trees and taller seedlings were predominantly red maple (Acer rubrum L.), flowering dogwood (Cornus florida L.), blackgum (Nyssa sylvatica Marsh.), and black cherry (Prunus serotina Ehrh.). Oaks less than 3 ft tall were abundant, but taller oak seedlings and saplings were uncommon. Tree mortality increased the proportion of white oak and hickories (Carya spp.) in the overstory, and stimulated a regeneration response of mostly non-oak species. South. J. Appl. For. 27(4):264–268.

Long-term mortality rates and spatial patterns in an old-growth Pinus resinosa forest

2013 ◽  
Vol 43 (9) ◽  
pp. 809-816 ◽  
Author(s):  
Emily J. Silver ◽  
Shawn Fraver ◽  
Anthony W. D’Amato ◽  
Tuomas Aakala ◽  
Brian J. Palik
Keyword(s):  
Spatial Pattern ◽  
Spatial Patterns ◽  
Pinus Banksiana ◽  
Tree Mortality ◽  
Stand Structure ◽  
Pinus Resinosa ◽  
Mortality Rates ◽  
Stand Age ◽  
Initial Population ◽  
Dead Trees

Understanding natural mortality patterns and processes of forest tree species is increasingly important given projected changes in mortality owing to global change. With this need in mind, the rate and spatial pattern of mortality was assessed over an 89-year period in a natural-origin Pinus resinosa (Aiton)-dominated system to assess these processes through advanced stages of stand development (stand age 120–209 years). Average annual mortality rates fluctuated through time, yet were within the range reported in other studies (0.60%–3.88% depending on species and sampling interval). Tree mortality was attributed to multiple agents, including the senescence of the short-lived Pinus banksiana Lamb., windthrow, root-rot fungi (Armillaria ostoyae (Romagn.) Herink), and perhaps infrequent droughts. Despite the often contagious nature of many disturbance agents, the overall spatial pattern of mortality events (the arrangement of dead trees within the fixed initial population of live trees) was random at all scales tested. Similarly, the current spatial pattern of dead trees was predominantly random, despite clustering at small scales (2–4 m). These findings underscore the importance of studying mortality rates, agents, and spatial patterns over long time periods to avoid misinterpreting stochastic mortality events, and their influence on longer term stand structure and development.

scholarly journals Site factors and stand conditions associated with Persian oak decline in Zagros mountain forests

2018 ◽  
Vol 26 (3) ◽  
pp. e014 ◽  
Author(s):  
Ahmad Hosseini ◽  
Seyed M. Hosseini ◽  
Juan C. Linares
Keyword(s):  
Climate Change ◽  
Tree Mortality ◽  
Stand Structure ◽  
Basal Area ◽  
Stand Density ◽  
Change Scenario ◽  
Climate Trends ◽  
Site Factors ◽  
Main Hypothesis ◽  
Shallow Soils

Aim of study: Drought and stand structure are major and interconnected drivers of forest dynamics. Water shortage and tree-to-tree competition may interact under the current climate change scenario, increasing tree mortality. In this study, we aimed to investigate climate trends, site and stand structure effects on tree mortality, with the main hypothesis that drought-induced mortality is higher as competition increases.Area of study: Persian oak forests from Zagros Range, western Iran.Material and Methods: We split the study area into 20 topographical units (TUs), based on aspect, slope and elevation. In each TU, three 0.1 ha plots were established to quantify site and stand characteristics, namely the diameter of all trees and shrubs, stand density and basal area, canopy dieback and mortality. In addition, soil profiles were analyzed to obtain physical and chemical soil properties. Six transects 100 m length were established per TU to measure tree-to-tree competition for alive and dead trees.Main Results: The highest mortality rates and crown dieback were found at higher elevations and southern and western aspects. Our findings confirm increasing rates of tree mortality in stands with higher tree density and shallow soils. As regard links between climate change and forest decline, our results suggest that changing forest structure may have a significant impact on dust emission.Research highlights: Despite severe dry years occurred recently the study area, they are not significantly different than those recorded in the past. Stand structure appears as a modulating factor of climate change effects, linked to competition-related tree vulnerability to drought.

The aftermath of tree death: coarse woody debris and the topography in four tropical rain forests

2000 ◽  
Vol 30 (9) ◽  
pp. 1489-1493 ◽  
Author(s):  
Neil Gale
Keyword(s):  
Coarse Woody Debris ◽  
Woody Debris ◽  
Basal Area ◽  
Slope Position ◽  
Tropical Rain Forests ◽  
Rain Forests ◽  
Dead Tree ◽  
Dead Trees ◽  
Relationship Of ◽  
The Relationship

The relationship of coarse woody debris (CWD) was examined with respect to topography and site in four lowland tropical rain forests in northern Borneo and western Ecuador. In total, 1914 dead trees [Formula: see text]20 cm diameter at breast height were enumerated in 46 ha. The basal area per hectare of dead trees varied strongly with both site and slope position. Dead basal area and its correlate dead tree density increased moving up the topographic gradient from the valleys to the ridges. Site estimates for CWD volume ranged from 96 to 154 m3·ha-1. Mean standing CWD volume was four times higher on the ridge tops (54 m3·ha-1) compared with the valley and cross-terrain areas (both 13 m3·ha-1). In contrast, downed volume did not vary with slope position. The proportions of CWD present as standing wood were two to three times higher in the Bornean sites compared with Hoja Blanca. These topographical and site differences in CWD were linked to differences in mode of tree death as well as the distribution of live trees per hectare.

Do biomass removal and structure-enhancing treatments influence deadwood characteristics following commercial thinning in spruce plantations in New Brunswick, Canada?

2015 ◽  
Vol 45 (10) ◽  
pp. 1407-1418 ◽  
Author(s):  
Kwadwo Omari ◽  
David A. MacLean
Keyword(s):  
New Brunswick ◽  
Picea Glauca ◽  
Woody Debris ◽  
Basal Area ◽  
Status Quo ◽  
Commercial Thinning ◽  
Dead Trees ◽  
Biomass Removal ◽  
The Status ◽  
Intensively Managed

Effects of commercial thinning on downed coarse woody debris (CWD) and standing dead trees (snags) were examined in six intensively managed 22- to 30-year-old white spruce (Picea glauca (Moench) Voss) plantations in northern New Brunswick, Canada. Four alternative treatments were applied: (i) an unthinned control and three commercial thinning 40% basal area removals, with (ii) slash and tops remaining on the site (status quo), (iii) most of the branches and tops extracted from the site (biomass removal), and (iv) clumps of unthinned trees left, with one-half of the trees in each clump girdled to create snags (enhanced structure). Three years after thinning, CWD volume increased by 14%–27% in the status quo and enhanced structure treatments, by 6% in the biomass removal treatment, and by 0.1% in the unthinned treatment. Mean snag volume changed little, i.e., less than 1 m3·ha−1 among treatments, and stumps of thinned trees were 4.6–4.9 m3·ha−1. The girdled trees added 0.7 m3·ha−1 of snags, and 1.3 m3·ha−1 is expected to be added from girdling the remaining live trees in the unthinned clumps in 2016. The girdled trees and future to-be-girdled trees added up to 50% of the new deadwood in the enhanced structure treatments, but thinning treatments did not significantly affect total deadwood. The results indicate that commercial thinning produced fine debris but had little effect on overall deadwood amount. Girdling trees during commercial thinning, at the intensity used in this study, is unlikely to produce sufficient snags. Leaving islands and clumps during harvest before plantation establishment would be a more effective way of adding structure.

Woodland mouse and vole response to increased structural diversity following midrotation commercial thinning in spruce plantations

2015 ◽  
Vol 45 (8) ◽  
pp. 1121-1131 ◽  
Author(s):  
Evan C. Dracup ◽  
Daniel M. Keppie ◽  
Graham J. Forbes
Keyword(s):  
Picea Glauca ◽  
Structural Changes ◽  
Woody Debris ◽  
Basal Area ◽  
Structural Diversity ◽  
Understory Vegetation ◽  
Deer Mice ◽  
Mammal Species ◽  
Commercial Thinning ◽  
Debris Removal

We assessed whether commercially thinning (CT) spruce (Picea spp.) plantations (40% basal area removal) can cause structural changes in fine woody debris (FWD) and understory vegetation to improve habitat quality for small rodents in northwestern New Brunswick, Canada. We created three contrasting environments (FWD rich – understory vegetation rich, FWD poor – understory vegetation rich, and FWD poor – understory vegetation poor) by establishing CT with debris retention (merchantable trunk removal), CT with all debris removed (full tree removal), and non-CT (plantation without CT) in six midrotation white spruce (Picea glauca (Moench) Voss) plantations. We live-trapped small mammals in each plantation during spring and summer of 2011 and 2012 and estimated animal density and survival with capture–recapture models. Southern red-backed vole (Myodes gapperi (Vigors, 1830)) density was two to three times greater in CT with debris retention than in either non-CT or CT with debris removal, and their survival rate was twice that in CT with debris removal. Woodland jumping mouse (Napaeozapus insignis (Miller, 1891)) density was two to five times greater in non-CT than in either CT treatment. Deer mice (Peromyscus maniculatus (Wagner, 1845)) did not show any treatment effect. Productivity and demographics were not affected by CT treatment for any species. We found evidence that midrotation spruce plantations are used differently by small mammal species based on stand condition and recommend that managers maintain plantations in CT and non-CT states.

Sign in / Sign up

Export Citation Format

Share Document