scholarly journals Stand Structure of Northern Taiga Pine Forests

2021 ◽  
pp. 86-105
Author(s):  
Ivan Kutyavin ◽  
◽  
Aleksey Manov ◽  
Andrey Osipov ◽  
Mikhail Kuznetsov ◽  
...  
Keyword(s):  
Age Structure ◽  
Stand Structure ◽  
Close Correlation ◽  
Northern Taiga ◽  
Komi Republic ◽  
Pine Forests ◽  
Tree Age ◽  
Green Moss ◽  
Three Generations ◽  
Pine Trees

In Northern taiga conditions pine forests occupy about 1.8 mln ha of the territory of the Komi Republic and are mainly represented by sphagnum, green-moss and lichen forest types. The studies were carried out at the Zelenoborsk Forest Station of the Institute of Biology of the Komi Scientific Centre of the Ural Branch of the Russian Academy of Sciences in green-moss and sphagnum pine forests developing at the site of fires and clearcuts. Tree layer has a mix composition with the predominance of pine trees and admixture of spruce, birch, larch and aspen. Pine stands form three types of age structure: conventionally evenaged; conventionally uneven-aged, represented by one generation; and stepped uneven-aged, consisting of two or three generations of pine trees. Trees left behind during clearcut and felling residuals at the cutting area by the burn method contribute to the formation of stands of stepped uneven-aged age structure. The variation coefficients of tree age are 5.8–10.8 % in pine forests with one generation and 39.7–45.6 % in forests with two or three generations. The number of generations and the type of age structure had no effect on the diameter and height of trees in the stand, which varied respectively within 25.2–49.5 % and 15.7–27.8 %. In pine forests developing after fires, the peak of pine settlement occur in the second or third decade, while in cutting areas, the maximum renewal occurs in the first or second decade after clearcuts. The amplitude of tree age fluctuations varies from 16 to 33 years in conventionally even-aged and conventionally uneven-aged forests developed after clearcuts and from 30 to 45 years in post-fire stands. In stepped uneven-aged stands tree age fluctuations changes from 120 to 167 years, and from 22 to 66 years in generations. The curves showing the distribution of trees by diameter in stands of pine trees had a left-handed shift, the asymmetry is represented by positive values and varies from 0.05 to 1.03. Trees of associate species are inferior in development, both in diameter and in height to pine trees of similar age. A close correlation between the diameter and height of trees in the stands was revealed. The relationship of age with diameter and height of trees varies from weak to significant at almost all of the sites studied. A close correlation between age and diameter was found in stepped uneven-aged pine forests (R = 0.79–0.96). The correlation between diameter and age increase with an increase in tree age fluctuations amplitude.

Root reinforcement in plantations of Cryptomeria japonica D. Don: effect of tree age and stand structure on slope stability

2008 ◽  
Vol 256 (8) ◽  
pp. 1517-1526 ◽  
Author(s):  
Marie Genet ◽  
Nomessi Kokutse ◽  
Alexia Stokes ◽  
Thierry Fourcaud ◽  
Xiaohu Cai ◽  
...  
Keyword(s):  
Slope Stability ◽  
Cryptomeria Japonica ◽  
Stand Structure ◽  
Tree Age ◽  
Root Reinforcement

scholarly journals Estimation of crown and canopy cover from airborne lidar data

2010 ◽  
Vol 52 (1) ◽  
pp. 5-17 ◽  
Author(s):  
Mait Lang
Keyword(s):  
Norway Spruce ◽  
Scots Pine ◽  
Stand Structure ◽  
Canopy Cover ◽  
Airborne Lidar ◽  
Silver Birch ◽  
Lidar Data ◽  
Crown Cover ◽  
Pine Trees ◽  
Airborne Lidar Data

Metsa katvuse ja liituse hindamine lennukilt laserskanneriga Tests were carried out in mature Scots pine, Norway spruce and Silver birch stands at Järvselja, Estonia, to estimate canopy cover (K) and crown cover (L) from airborne lidar data. Independent estimates Kc and Lc for K and L were calculated from the Cajanus tube readings made on the ground at 1.3 m height. Lidar data based cover estimates depended on the inclusion of different order returns significantly. In all the stands first order return based estimate K1 was biased positively (3-10%) at the reference height of 1.3 m compared to ground measurements. All lidar based estimates decreased with increasing the reference height. Single return (Ky) and all return (Kk) based canopy cover estimates depended more on the sand structure compared to K1. The ratio of all return count to the first return count D behaved like crown cover estimate in all stands. However, in spruce stand D understimated Lc significantly. In the Scots pine stand K1(1.3) = 0.7431 was most similar canopy cover estimate relative to the ground estimate Kc = 0,7362 whereas Ky(1.3) and Kk(1.3) gave significant underestimates (>15%) of K. Caused by the simple structure of Scots pine stand - only one layer pine trees, the Cajanus tube based canopy cover (Kc), crown cover (Lc) and lidar data based canopy density D(1.3) values were rather similar. In the Norway spruce stand and in the Silver birch stand second layer and regeneration trees were present. In the Silver birch stand Kk(1.3) and Ky(1.3) estimated Kc rather well. In the Norway spruce stand Ky(1.3) and K1(1.3) were the best estimators of Kc whereas Kk(1.3) underestimated canopy cover. Lidar data were found to be usable for canopy cover and crown cover assessment but the selection of the estimator is not trivial and depends on the stand structure.

scholarly journals Modification of Fire Regimes Inferred from the Age Structure of Two Conifer Species in a Tropical Montane Forest, Mexico

Forests ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1193 ◽  
Author(s):  
Jesús Eduardo Sáenz-Ceja ◽  
Diego Rafel Pérez-Salicrup
Keyword(s):  
Age Structure ◽  
Altitudinal Gradient ◽  
Biosphere Reserve ◽  
Fire Regimes ◽  
Monarch Butterfly ◽  
Pine Forests ◽  
Conifer Forests ◽  
Tree Establishment ◽  
Low Intensity ◽  
Mixed Conifer Forests

Research Highlights: Age structure was used to infer fire regimes in the Monarch Butterfly Biosphere Reserve. Uneven-aged structures in stands dominated and co-dominated by pine and fir species, which are distributed according to an altitudinal gradient, indicated a regime of frequent, low-severity, and low-intensity fires. Background and Objectives: Age structure analyses have been used to infer natural and disrupted fire regimes when field-based descriptions of fires are scarce or unavailable. In montane conifer forests, fire regimes typically vary according to an altitudinal gradient, shaping contrasting tree establishment patterns. In the Monarch Butterfly Biosphere Reserve, Mexico, the altitudinal distribution and fire regimes of sacred fir forests (Abies religiosa), smooth-bark Mexican pine forests (Pinus pseudostrobus), and mixed-conifer forests are poorly documented. The objectives of this study were to determine the altitudinal ranges occupied by mono-dominant and co-dominant stands and to reconstruct tree establishment history to infer historical fire regimes. Materials and Methods: Six altitudinal transects were established along the reserve, each one at elevations from 2400 to 3300 m, with sampling sites at every 150 m of elevation. In each site, increment cores were collected from the base of 25 mature trees. A total of 800 increment cores were collected and cross-dated. Results: P. pseudostrobus is dominant in stands between 2400 and 2850 m, A. religiosa between 3150 and 3300 m, and both species co-dominate between 2850 and 3150 m. The establishment pattern for both species has been continuous, represented by uneven-aged structures, suggesting that tree establishment in smooth-bark Mexican pine forests, mixed-conifer forests, and sacred fir forests, is likely to be associated with frequent, low-severity, and low-intensity fires. Conclusions: These fire regimes suggest, by the one hand, the disruption of natural fire regimes by human activities, limiting the occurrence of high-severity fires; on the other hand, a distinctive feature of these tropical montane forests.

Pine chemical volatiles promote dauer recovery of a pine parasitic nematode, Bursaphelenchus xylophilus

Parasitology ◽  
2019 ◽  
Vol 147 (1) ◽  
pp. 50-57 ◽  
Author(s):  
Wei Zhang ◽  
Yongxia Li ◽  
Long Pan ◽  
Xuan Wang ◽  
Yuqian Feng ◽  
...  
Keyword(s):  
Parasitic Nematode ◽  
Pine Wilt Disease ◽  
Bursaphelenchus Xylophilus ◽  
Wilt Disease ◽  
Pine Forests ◽  
Pinewood Nematode ◽  
Dispersal Stage ◽  
Pine Trees ◽  
The Common ◽  
Gradient Effects

AbstractPinewood nematode, Bursaphelenchus xylophilus, a pine parasitic nematode, poses a serious threat to its host pine forests globally. When dispersal-stage larvae 4 (dauer, DL4) of B. xylophilus enters the new pine, it moults into propagative adult (dauer recovery) and reproduces quickly to kill the host pine. Here, we found pine chemical volatiles, rather than the common dauer recovery factors of nematodes (e.g. suitable temperatures, nutrient availability or density), promote B. xylophilus dauer recovery. The results showed that volatilization of chemicals in host pines could attract DL4 and promote DL4 recovery. To identify which chemicals promote this process, we determined the stimulated activity of the main volatiles of pines including six monoterpenes and two sesquiterpenes. Results showed that all the six monoterpenes promoted dauer recovery, especially β-pinene and β-myrcene, but the two sesquiterpenes have no effect on the transformation. Furthermore, β-pinene performed gradient effects on dauer recovery. We hypothesized that when DL4 infect pine trees, the pine volatiles released from the feeding wounds are used as chemical signals for DL4 transformation to adult to reproduce and rapidly kill the pines. Our study identified the B. xylophilus dauer recovery chemical signal and may contribute to preventing pine wilt disease.

Simulated fire behaviour in young, postfire lodgepole pine forests

2017 ◽  
Vol 26 (10) ◽  
pp. 852 ◽  
Author(s):  
Kellen N. Nelson ◽  
Monica G. Turner ◽  
William H. Romme ◽  
Daniel B. Tinker
Keyword(s):  
Pinus Contorta ◽  
Stand Structure ◽  
Lodgepole Pine ◽  
Pine Forests ◽  
Fuel Moisture ◽  
Crown Fire ◽  
Fire Behaviour ◽  
Fire Initiation ◽  
Moisture Conditions ◽  
Simulated Fire

Early-seral forests are expanding throughout western North America as fire frequency and annual area burned increase, yet fire behaviour in young postfire forests is poorly understood. We simulated fire behaviour in 24-year-old lodgepole pine (Pinus contorta var. latifolia) stands in Yellowstone National Park, Wyoming, United States using operational models parameterised with empirical fuel characteristics, 50–99% fuel moisture conditions, and 1–60kmhr−1 open winds to address two questions: [1] How does fireline intensity, and crown fire initiation and spread vary among young, lodgepole pine stands? [2] What are the contributions of fuels, moisture and wind on fire behaviour? Sensitivity analysis indicated the greatest contributors to output variance were stand structure mediated wind attenuation, shrub fuel loads and 1000-h fuel moisture for fireline intensity; crown base height for crown fire initiation; and crown bulk density and 1-h fuel moisture for crown fire spread. Simulation results predicted crown fire (e.g. passive, conditional or active types) in over 90% of stands at 50th percentile moisture conditions and wind speeds greater than 3kmhr−1. We conclude that dense canopy characteristics heighten crown fire potential in young, postfire lodgepole pine forests even under less than extreme wind and fuel moisture conditions.

Factors controlling epiphytic lichen biomass during postfire succession in black spruce boreal forests

2009 ◽  
Vol 39 (11) ◽  
pp. 2168-2179 ◽  
Author(s):  
Catherine Boudreault ◽  
Yves Bergeron ◽  
Darwyn Coxson
Keyword(s):  
Boreal Forests ◽  
Stand Structure ◽  
Black Spruce ◽  
Tree Age ◽  
Stand Age ◽  
Epiphytic Lichens ◽  
Dominant Group ◽  
Epiphytic Lichen ◽  
Structure Tree ◽  
Species Groups

Alectorioid lichens are the dominant group of epiphytic lichens in boreal forests. Epiphytic lichen richness and abundance generally increase with stand age and within-stand heterogeneity. The objective of this study was to evaluate the importance of time elapsed since the last fire, stand structure, tree size, tree age, and branch height for epiphytic lichen biomass of the boreal forest of western Quebec. We sampled 12 sites belonging to four forest age classes (from 50 to >200 years). We assessed epiphytic lichen biomass of three species groups ( Bryoria , Evernia , and Usnea ) on 12 trees in each site. Our results showed that biomass of Bryoria and Usnea was higher in intermediate stages (between 101 and 200 years) compared with younger (50–100 years) and older (>200 years) stages. Biomass of the three species groups was greater on larger diameter trees (>16 cm) compared with smaller ones (<16 cm). These results indicate that the protection of postfire stands aged between 101 and 200 year should be prioritized to maintain the functional role of epiphytic lichens in managed landscapes.

Effect of thinning and prescribed burning on crown fire severity in ponderosa pine forests

2002 ◽  
Vol 11 (1) ◽  
pp. 1 ◽  
Author(s):  
Jolie Pollet ◽  
Philip N. Omi
Keyword(s):  
Prescribed Fire ◽  
Ponderosa Pine ◽  
Stand Structure ◽  
Fire Severity ◽  
Fire Effects ◽  
Pine Forests ◽  
Crown Fire ◽  
Fuel Treatments ◽  
Ponderosa Pine Forests ◽  
Wildfire Hazard

Fire exclusion policies have affected stand structure and wildfire hazard in north American ponderosa pine forests. Wildfires are becoming more severe in stands where trees are densely stocked with shade-tolerant understory trees. Although forest managers have been employing fuel treatment techniques to reduce wildfire hazard for decades, little scientific evidence documents the success of treatments in reducing fire severity. Our research quantitatively examined fire effects in treated and untreated stands in western United States national forests. Four ponderosa pine sites in Montana, Washington, California and Arizona were selected for study. Fuel treatments studied include: prescribed fire only, whole-tree thinning, and thinning followed by prescribed fire. On-the-ground fire effects were measured in adjacent treated and untreated forests. We developed post facto fire severity and stand structure measurement techniques to complete field data collection. We found that crown fire severity was mitigated in stands that had some type of fuel treatment compared to stands without any treatment. At all four of the sites, the fire severity and crown scorch were significantly lower at the treated sites. Results from this research indicate that fuel treatments, which remove small diameter trees, may be beneficial for reducing crown fire hazard in ponderosa pine sites.

Large herbivores control the invasive potential of nonnative Austrian black pine in a mixed deciduous Mediterranean forest

2006 ◽  
Vol 36 (4) ◽  
pp. 1047-1053 ◽  
Author(s):  
Sandrine Chauchard ◽  
Gaëlle Pille ◽  
Christopher Carcaillet
Keyword(s):  
Age Structure ◽  
Structural Changes ◽  
Deciduous Forest ◽  
Bos Taurus ◽  
Pinus Nigra ◽  
Tree Age ◽  
Black Pine ◽  
Invasive Potential ◽  
Large Herbivores ◽  
Eastern Pyrenees

The invasive potential of the nonnative Austrian black pine (Pinus nigra subsp. nigra Arn.) was analyzed in a 100-year-old Mediterranean mixed deciduous forest in the Massane Nature Reserve, eastern Pyrenees (France). The reserve holds approximately 120–150 semiferal cattle (Bos taurus L.) that browse and trample the woody regeneration. Tree age structure was assessed by dendrochronology to reconstruct the pine population dynamics in grazed and nongrazed (fenced in 1954) portions of the forested reserve. The age structure of the pine population regenerating before 1960 was similar between the inside and outside of the enclosed reserve area. Since 1960, pine recruitment has occurred only in the nongrazed area. The diameter variability with age changed since the 19th century. For pines less than 20 years old, the diameter variability is low, whereas it is very high for individuals older than 100 years. Diverse forest structural changes (composition, canopy height, density, etc.) likely explain the variability in diameter at a given age. Cattle do not appear to affect tree growth as it is similar inside and outside the fenced area, but they control the regeneration of nonnative Austrian black pines, which can spread in the absence of cattle. If nonnative black pine poses a risk for forest conservation, large herbivores may play a useful role in maintaining this species at low abundance.

The influence of spruce on acidity and nutrient content in soils of Northern Taiga dwarf shrub–green moss spruce forests

2016 ◽  
Vol 49 (11) ◽  
pp. 1276-1287 ◽  
Author(s):  
M. A. Orlova ◽  
N. V. Lukina ◽  
V. E. Smirnov ◽  
N. A. Artemkina
Keyword(s):  
Nutrient Content ◽  
Northern Taiga ◽  
Dwarf Shrub ◽  
Green Moss ◽  
Spruce Forests

Hydrocarbons content in soils of the northernmost taiga ecosystem of Komi Republic (North-East of Russia)

2017 ◽  
Vol 7 (2) ◽  
pp. 248-256 ◽  
Author(s):  
Evgeny Dmitrievich Lodygin ◽  
Vasily Aleksandrovich Beznosikov ◽  
Evgeny Vasil'evich Abakumov
Keyword(s):  
Soil Cover ◽  
Northern Taiga ◽  
Komi Republic ◽  
Parent Material ◽  
Background Concentrations ◽  
Forming Process ◽  
North East ◽  
Texture Class

The background concentrations of hydrocarbons (HCs) were estimated for soils of the northernmost and northern taiga ecosystem of the Komi Republic. It was shown that accumulation and distribution of hydrocarbons in soil cover is regulated by following pedological factors: texture class, parent material and landform type and the type of soil forming process. In all studied soils of accumulative positions showed more pronounces accumulation of hydrocarbons than the soils of well-drained eluvial positions. Interprofile differentiation of hydrocarbons content is more expressed in clay-textured soils than sandy ones.

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