scholarly journals Effect of Removal of Standing Dead Material on Growth of Agropyron spicatum

1978 ◽  
Vol 31 (2) ◽  
pp. 121 ◽  
Author(s):  
Ronald H. Sauer

1996 ◽  
Vol 76 (4) ◽  
pp. 555-562 ◽  
Author(s):  
G. A. Houseal ◽  
B. E. Olson

On northern latitude winter rangelands, the effects of low forage nutritive value on animal performance are usually mitigated by supplementing livestock, although the amount of supplement is often not adjusted for available forage quantity and nutritive value. The objective of this study was to assess the potential of live (fall, spring) and dead component of two cool-sea-son bunchgrasses to meet nutritional requirements of cattle from fall through spring on a foothills range site in southwestern Montana. Several nutritive characteristics of live and dead components of bluebunch wheatgrass (Pseudoroegneria spicata [Pursh] A. Love) and Idaho fescue (Festuca idahoensis Elmer) were assessed during the winters of 1991–1992 and 1992–1993. In addition, rate and extent of dry matter disappearance, and extent of crude protein disappearance were determined in-situ using ruminally cannulated beef cows. Nutritive value of forage components of bluebunch wheatgrass and Idaho fescue were similar fall through spring. Fall growth was similar in CP and digestibility to April growth, and maintained these levels through winter. With normal forage intake rates on winter range, CP levels of standing dead material would not meet animal protein requirements fall through spring. When fall growth is not abundant, more protein supplement would be needed than when it is abundant. Matching animal requirements to forage availability and nutritive value, supplementing only when necessary and in appropriate amounts, could help reduce costs of winter feeding. Key words: Winter grazing, bluebunch wheatgrass, Idaho fescue, forage quality, cattle



1980 ◽  
Vol 33 (4) ◽  
pp. 314
Author(s):  
Forrest A. Sneva
Keyword(s):  


1994 ◽  
Vol 59 ◽  
Author(s):  
TH. Zagas

Development of the evergreen broadleaved ecosystems after a  forest fire in Athos. - The peninsula of Athos is  the third eastern peninsula of Chalkidiki in Central Macedonia (N. Greece)  and it constitutes a self-governed region in the Hellenic State. Its  organized monastic history begins in the 10th century and continues  uninterruptedly until today. The monastery of Simonopetra, one of the 20  monasteries of Athos, represents a continuous historic life of seven  centruries from its establishment, during the 13th century and constitutes  the most during edifice on Mount Athos, a miracle of the byzantine and  post-byzantine architecture.     The territory of Simonopetra on Mount Athos, occupies an area of 1265 ha.  The destructive forest fire on Mount Athos which started on August 14, 1990,  was extinguished 14 days later. During this period, it caused heavy damage to  the forests on the peninsula and destroyed a number of historical buildings.  Most of the damage occured in the area of the Sacred Monastery Simonopetra,  where 855 ha of the total of 1265 ha were burned.     The greatest part of the burned forest area, about 665 ha, they were  evergreen broadleaved forests. The ecosystems of the evergreen broadleaved  forests are perscribed as well as their development after the forest fire.  After the fire, all species which appear in this zone, begun to coppice  sprout in a few weeks and after two years, the coppicing sprouts exceeded in  height 0,5 - 2 metres depended on the species and site quality. Two years  after the fire the vegetation was restored and covered 30 - 76% of the area.      The only measure taken in certain positions was the removal of the standing  dead material.



Forests ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 503
Author(s):  
Andrew Giunta ◽  
John Shaw

Downed woody material (DWM) is a key component in forest ecosystems with age, structure, and disturbance described as primary factors that influence DWM dynamics. In particular, much emphasis is placed on large coarse woody debris (CWD). Fine woody debris (FWD) (less than 7.62 cm diameter), duff, and litter also contribute to carbon stocks, provide habitat, add to nutrient cycling, and are often the most available fuels for fire, yet are regularly overlooked in studies describing the forest floor. Throughout the middle montane zone within the Intermountain West region USA, interior Douglas-fir (Pseudotsuga menziesii var. glauca Mirb. Franco) is a predominant forest type, yet little is known about the forest floor complex in these forests. We used a chronosequence approach to compare DWM patterns over the course of stand development among stands with different disturbance histories. Using classification and regression trees, we also evaluated an assemblage of environmental, structural, and disturbance variables to determine factors of most importance for estimating loading for DWM, duff, and litter. We found CWD resembled a U-shaped pattern of buildup while FWD components remained stable over the course of stand development regardless of disturbance history. Our results indicate that large DWM components are most closely associated with the amount of standing dead material in a stand, primarily the density and basal area of snags. Fine woody material was more aligned with live stand components, while duff and litter were more influenced by disturbance.



2019 ◽  
Vol 11 (22) ◽  
pp. 2614 ◽  
Author(s):  
Nina Amiri ◽  
Peter Krzystek ◽  
Marco Heurich ◽  
Andrew Skidmore

Knowledge about forest structures, particularly of deadwood, is fundamental for understanding, protecting, and conserving forest biodiversity. While individual tree-based approaches using single wavelength airborne laserscanning (ALS) can successfully distinguish broadleaf and coniferous trees, they still perform multiple tree species classifications with limited accuracy. Moreover, the mapping of standing dead trees is becoming increasingly important for damage calculation after pest infestation or biodiversity assessment. Recent advances in sensor technology have led to the development of new ALS systems that provide up to three different wavelengths. In this study, we present a novel method which classifies three tree species (Norway spruce, European beech, Silver fir), and dead spruce trees with crowns using full waveform ALS data acquired from three different sensors (wavelengths 532 nm, 1064 nm, 1550 nm). The ALS data were acquired in the Bavarian Forest National Park (Germany) under leaf-on conditions with a maximum point density of 200 points/m 2 . To avoid overfitting of the classifier and to find the most prominent features, we embed a forward feature selection method. We tested our classification procedure using 20 sample plots with 586 measured reference trees. Using single wavelength datasets, the highest accuracy achieved was 74% (wavelength = 1064 nm), followed by 69% (wavelength = 1550 nm) and 65% (wavelength = 532 nm). An improvement of 8–17% over single wavelength datasets was achieved when the multi wavelength data were used. Overall, the contribution of the waveform-based features to the classification accuracy was higher than that of the geometric features by approximately 10%. Our results show that the features derived from a multi wavelength ALS point cloud significantly improve the detailed mapping of tree species and standing dead trees.



With the exception of some of the parasitic orders, such as the Balanophoraceœ , there are probably no families of flowering plants—one might almost include flowerless—which are so completely transformed from the average or mesophytic type of the phanerogams into types which are so completely unique and peculiar, as the Tristichaceæ and still more the Podostemaceæ. Nor are there any in which, with such very great uniformity in the conditions of life, there is such remarkable variety in the morphological structure. The structure of the orders, or rather of their members, being unique, and the conditions under which they live being also unique, it has been taken for granted that the former is in a high degree adapted to the latter, the flat thallus-like expansions of stem or root being looked upon as admirably suited to the rushing water in which they live. So long as we were almost completely ignorant of the actual living plants, and content with dead material collected mainly in the dry seasons, this was all very well, but now that for 17 years I have devoted much attention to these plants,* have studied them in the living condition in their natural habitats in India, Ceylon, and Brazil, have followed them from germination right through their life-history, and in other ways become absolutely familiar with them, and as a result of all this have arrived at diametrically opposite conclusions, it will repay us to examine into the question in some detail.



2008 ◽  
Vol 84 (3) ◽  
pp. 392-400
Author(s):  
Steen Magnussen ◽  
Dave Harrison

The number and size of checks, wood moisture content, extent of blue-stain, rot and decay was examined by stem analysis in 360 mature standing beetle-killed lodgepole pines. Trees came from three areas (Burns Lake, Quesnel, and Vanderhoof) in Central British Columbia. Each area was represented by 14 to 16 sampling areas (stands) distributed evenly across three soil moisture regimes (dry, mesic, wet). Year of death was estimated from tree ring-analysis, local knowledge and insect and disease survey maps. An approximately equal number of trees had been dead for one or two years, three or four years, or for five or more years. During the first five years since death by beetle attack the number of checks per tree increased from 2.5 to 10.2 and the average depth of checks increased from 4.3 cm to 5.1 cm. Checks were deeper, wider, and longer on the drier sites than on mesic and wet sites. Moisture content of sapwood and heartwood was near the fibre saturation point (ca 30%) one year after death and continued to decrease at a rate of approximately 1.7% per year. Both the incidence and the extent (relative to basal area) of rot and decay increased significantly with time since death. All trees had an extensive blue-stain discoloration. Deterioration of wood quality was fastest during the first two years after a beetle attack. Key words: wood checks, moisture content, blue-stain, wood quality, spiral grain, bark beetle



2008 ◽  
Vol 38 (10) ◽  
pp. 2616-2625 ◽  
Author(s):  
Raul Rosenvald ◽  
Asko Lõhmus ◽  
Andres Kiviste

Survival of live retention trees is a key issue for stand-scale applications of natural-disturbance-based silviculture. We explored the survival of 3255 trees in 102 cut areas (mean size 2.3 ha) in Estonia for 6 years, focusing on spatial variation and preadaptation of the trees. Altogether, 35% of the trees died during the study period, contributing 4.4 m3 of downed dead trunks and 1 m3 of standing dead trees per hectare. The annual mortality rates declined over time. The main survival determinants were tree species (higher for hardwood deciduous trees), diameter (species dependent), position relative to forest edge (higher for trees near current or former forest edges), retention density (positive), and exposure (negative). The results suggest that (1) green-tree retention can effectively increase the abundance of large shade-tolerant trees, but it is equally important for producing deadwood; (2) larger individuals, former interior-forest trees near current forest edges, and preadapted trees in open conditions should be preferably retained; (3) there is no obvious necessity to modify tree-retention techniques for tree survival according to geographical region or forest site type.



1939 ◽  
Vol 66 (5) ◽  
pp. 327 ◽  
Author(s):  
Rexford F. Daubenmire
Keyword(s):  


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