Blog List

Saturday, 24 December 2016

Comparison of fixed-area plot designs for estimating stand characteristics and western spruce budworm damage in southwestern U.S.A. forests

Author
Various sampling designs were evaluated using data on stand density, stocking, mortality, and top kill, as influenced by the western spruce budworm (Choristoneura occidentalis Freeman) in 17 stands in New Mexico and Colorado. Efficiency improved as plot size decreased from 0.04 to 0.02 ha for all variables and sampling designs, except for 0.01-ha plots, which required extremely large sample sizes and were subject to bias. Cluster designs were much more efficient than simple random sampling designs, allowing twice the reduction in sample size than was gained by relaxing the allowable error from 10 to 15%. Clusters of two plots were as precise as clusters of three plots. Of the four variables evaluated, density required the largest sample sizes, followed by stocking, percent mortality (for stands where mortality exceeded 10%), and top kill. Few plots were necessary to ascertain that mortality was less than 10%. On average, 10 pairs of 0.02-ha plots would estimate density, stocking, and mortality within a 10% allowable error. A field check of density and stocking variables is recommended, and additional samples are suggested in stands with large percent standard errors associated with those variables.

For further information log on website :
http://www.nrcresearchpress.com/doi/abs/10.1139/x03-033#/doi/abs/10.1139/x03-055

Stand structure governs the crown collisions of lodgepole pine

Author
We investigated tree sway and crown collision behavior of even-aged lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) stands of different structure in Alberta, Canada, to examine how these factors might affect loss of leaf area as stands mature. The Two Creeks stand (TC) had high density and slender trees, while the Chickadee stand (CH) had stout trees. The TC stand was then thinned (TCT) to reduce the stand density. For each stand, simultaneous tree sways of a group of 10 trees were monitored with biaxial clinometers during wind speed of 5 m/s (canopy top). Crown collisions were reconstructed by combining sway displacement of individual trees with their respective crown dimensions. Comparing the sway statistics between stands with contrasting mean bole slenderness (TC and CH) indicated that more slender trees have greater sway displacements, faster sway speeds, and a greater depth of collision. Disturbance by thinning increased sway displacements, sway speeds, and depth of collisions at TCT. Tree sway patterns were circular in shape and not aligned with wind direction, but patterns were elongated after thinning. This demonstrates the high frequency of crown collision experienced by stands with slender trees and supports the notion that crown collisions result in empty space between crowns of trees.

For further information log on website :
http://www.nrcresearchpress.com/doi/abs/10.1139/x03-033

Are mixed-species stands more productive than single-species stands: an empirical test of three forest types in British Columbia and Alberta

Author
Stand volumes were determined for naturally established, even-aged, single- and mixed-species stands involving three combinations of shade-tolerant and shade-intolerant conifers on similar sites: (i) western redcedar – western hemlock (Thuja plicata Donn ex D. Don – Tsuga heterophylla (Raf.) Sarg.), (ii) lodgepole pine – western larch (Pinus contorta Dougl. ex Loud. – Larix occidentalis Nutt.), and (iii) lodgepole pine – black spruce (Pinus contorta – Picea mariana (Mill.) BSP). Stand volume was significantly increased with site index and breast-height age in all three studies. Stand volume was also related to relative stand density in the lodgepole pine – black spruce study. When both species were shade tolerant (hemlock–redcedar), stand volume increased linearly with the proportion of hemlock; the mixed-species stands had intermediate volume compared with single-species stands. The combination of two shade-intolerant species (pine–larch) had lower stand volume than that anticipated from single-species stands, implying that one species may inhibiting the growth of the other. Mixtures of shade-intolerant and shade-tolerant species with different growth patterns (spruce–pine) may be more productive than single-species stands in specific ecological contexts and developmental stages. The effect of one species on the productivity of another species is tree-species and site specific: at maturity, even-aged, mixed-species coniferous stands are not necessarily more productive than single-species stands.

For further information log on website :
http://www.nrcresearchpress.com/doi/abs/10.1139/x03-033

A chronosequence of wood decomposition in the boreal forests of Russia

Author

Coarse woody debris (CWD), represented by logs and snags >10 cm in diameter and >1 m in length, was sampled at eight sites in Russian boreal forests to determine the specific density of decay classes and decomposition rates. Tree species sampled included Abies siberica Ledeb., Betula pendula Roth., Betula costata Trautv., Larix siberica Ledeb., Larix dahurica Turcz., Picea abies(L.) Karst., Picea obovata Ledeb., Picea ajanensisFisch., Pinus koraiensis Sieb. et Zucc., Pinus siberica Ledeb., Pinus sylvestris L., and Populustremula L. The mean densities for decay clas ses 1 through 5 ranged from 0.516 to 0.084 g·cm–3, respectively. Annual decomposition rates varied among the species, and for logs, decomposition rates ranged from 4.2 to 7.8% for B. pendula, 2.6 to 4.9% for Picea spp., 2.7 to 4.4% for Pinus sylvestris, 1.5 to 3.1% for Larix spp., and 1.5 to 1.9% for Pinus koraiensis and Pinus siberica. Logs decomposed faster than snags. Among the sites examined, temperature and precipitation did not correlate with decomposition rates, which is consistent with other studies in the boreal region. Globally, a positive correlation between decomposition and mean annual temperatures was found, with decay-resistant trees less responsive than those with low decay resistance.

For further information log on website :
http://www.nrcresearchpress.com/doi/abs/10.1139/x03-033

Long-term droughtiness and drought tolerance of eastern US forests over five decades

Author

Year Published

2015

Source

Forest Ecology and Management. 345: 56-64.

Abstract

Droughts can influence forest composition directly by limiting water or indirectly by intensifying other stressors that affect establishment, growth, and mortality. Using community assemblages of eastern US tree species and drought tolerance characteristics assessed from literature, we examine recent drought conditions in relation to the spatial distribution of species and their tolerance to drought. First we calculate and compare a cumulative drought severity index (CDSI) for the conterminous US for the periods 1960-1986 and 1987-2013 using climate division Palmer Drought Severity Index (PDSI) values and a gridded self-calibrated PDSI dataset. This comparison indicates that drought conditions in the East tend to be less frequent and generally less severe than those in the West, and that the West has had a large increase in CDSI values in the latter period. Then we focus on the past and potential future role of droughtiness in eastern forests, which are relatively more diverse than western forests but have individual species that are uniquely affected by drought conditions. We found that eastern US forests tend to be relatively balanced in the composition of drought-tolerant and -intolerant species and that drought conditions are relatively uncommon in the East. Understanding the composition and distribution of drought tolerance levels within forests is crucial when managing for the impacts of drought (e.g., managing for survival), especially given the expected rise of drought in the future.

Keywords

Citation


Peters, Matthew P.; Iverson, Louis R.; Matthews, Stephen N. 2015. Long-term droughtiness and drought tolerance of eastern US forests over five decades. Forest Ecology and Management. 345: 56-64.

For further details log on website :
https://www.nrs.fs.fed.us/pubs/47839

User's guide to SILVAH

Author

  • Knopp, Peter D.
  • Stout, Susan L.
  • Year Published

    2014

    Publication

    Gen. Tech. Rep. NRS-128. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station. 122 p.

    Abstract

    This user's guide for the SILVAH computer program, version 6.2, supersedes the 1992 user's guide (Gen. Tech. Rep. NE-162). Designed for stand-alone Windows-based personal computers, SILVAH recommends a silvicultural prescription for a forest stand based on a summary and analysis of field inventory data. The program also includes a simulator that can be used to project stand growth and development, estimating yields from either prescribed or user-defined treatments. The software is distributed with an online help system and this printed user's manual. The computer program described in this publication is available on the Internet at http://nrs.fs.fed.us/tools/silvah.

    Keywords

    Citation


    Knopp, Peter D.; Stout, Susan L. 2014. User's guide to SILVAH. Gen. Tech. Rep. NRS-128. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station. 122 p.

    For further details log on website :
    https://www.nrs.fs.fed.us/pubs/45873

    Prescribing regeneration treatments for mixed-oak forests in the Mid-Atlantic region

    Author

    Year Published

    2008

    Publication

    Gen. Tech. Rep. NRS-33. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station. 100 p.

    Abstract

    Includes guidelines for using the SILVAH decision-support system to perpetuate oak forests in the Mid-Atlantic region. Six chapters provide information on values of oak forests, inventory methods, key decision variables, decision charts, and silvicultural prescriptions, as well as guidance on fostering young stands. Sample tally sheets and SILVAH computer printouts are included in the Appendix.

    Keywords

    Citation


    Brose, Patrick H.; Gottschalk, Kurt W.; Horsley, Stephen B.; Knopp, Peter D.; Kochenderfer, James N.; McGuinness, Barbara J.; Miller, Gary W.; Ristau, Todd E.; Stoleson, Scott H.; Stout, Susan L. 2008. Prescribing regeneration treatments for mixed-oak forests in the Mid-Atlantic region. Gen. Tech. Rep. NRS-33. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station. 100 p.

    For further details log on website :
    https://www.nrs.fs.fed.us/pubs/8561

    Prescribing silvicultural treatments in hardwood stands of the Alleghenies. (Revised)

    Author

    Year Published

    1992

    Publication

    Gen. Tech. Rep. NE-96. Broomall, PA: U. S. Department of Agriculture, Forest Service, Northeastern Forest Experimental Station. 101 p.

    Abstract

    This publication brings together the results of 20 years of research and experience in the silviculture of hardwood forests in the Allegheny region. It provides a summary of silvicultural knowledge, and guidelines, decision tables, and step-by-step instructions for determining silviculutural prescriptions in individual stands. 

    Keywords

    Citation


    Marquis, David A.; Ernst, Richard L.; Stout, Susan L. 1992. Prescribing silvicultural treatments in hardwood stands of the Alleghenies. (Revised). Gen. Tech. Rep. NE-96. Broomall, PA: U. S. Department of Agriculture, Forest Service, Northeastern Forest Experimental Station. 101 p.

    For further details log on website :
    https://www.nrs.fs.fed.us/pubs/6294

    SILVAH 7 - Decision support for managers of Allegheny hardwood and mixed oak ecosystems

    Author

    SILVAH 7 - Decision support for managers of Allegheny hardwood and mixed oak ecosystems

    Scott Thomasma and Susan Stout

    [image:] Allegheny Hardwood Forest

    SILVAH (short for Silviculture of Allegheny Hardwoods, but now also applicable to mixed oak forests) is a computer tool for making silvicultural decisions in hardwood stands of the mid-Atlantic and upper Appalachian region. It is an "expert system" in that it recommends appropriate treatments based upon user objectives and overstory, understory, and site data provided by the user. SILVAH also contains a wildlife attributes report, forest stand growth simulator, provides the ability to test alternative cuts, enables development of a forest-wide inventory database, and facilitates other forest management planning functions. 
    SILVAH is the computerized implementation of a systematic approach to silviculture, in which current conditions are identified through a systematic inventory of overstory and understory.  These conditions are evaluated using an objective set of research-based standards and the constraints and objectives of the land-manager.  Then a prescription is recommended to move the stand closer to the manager’s objectives. The silviculture behind the SILVAH system in Allegheny, northern hardwood, and mixed-oak forests is described in two publications titled Prescribing silvicultural treatments in hardwood stands of the Alleghenies and Prescribing regeneration treatments for mixed-oak forests in the Mid-Atlantic region   
    SILVAH-7, Version 7.0, is available for download from our web site! SILVAH-7 is the successor to SILVAH 6.2, which will eventually be phased out. New features in SILVAH-7 include detailed understory inventory data entry (species by height class for seedlings and stump sprouts), enhanced wildlife reports and wildlife attributes for plant species, and the ability to see how changes in data or defaults affect recommended prescriptions in real time.  If you choose to download SILVAH-7, we would appreciate being notified if you find any problems when using the software.  A guide to data entry short-cuts for users who enter data directly into SILVAH is also available and quick reference guides for data collection are available below. The User's Guide to SILVAH may provide helpful background, although it was written for SILVAH 6 and there may be slight differences.

    More Information

    Downloads and Documentation
    SILVAH-7, version 7.0.2.32 (may require user to obtain administrative privileges to install) - Revised November 22, 2016exe
    (self-extracting zip file) 
    13 mb
    User's Guide to SILVAH 6.2pdf1.9 mb
    SILVAH Allegheny Hardwoods Quick Reference Guide pdf643 kb
    SILVAH Oak Quick Reference Guide pdf645 kb
    SILVAH Overstory Data Entry shortcutspdf21 kb
    Tally Sheets
    pdf 

      

    (Some documents on this page are in PDF format. You may obtain a free PDF reader from Adobe.)

    For further details log on website :
    https://www.nrs.fs.fed.us/tools/silvah7/

    Orangutan in the Swamp


    orang-utan of Borneo
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    Orangutan is a rainforest animal and it dislikes water, so I was surprised to see an orangutan foraging in swampy area of Kinabatangan last month. Actually this is not the first time it is found wandering in nypa forest, so I’m sure it wasn’t lost.
    nypa swamp
    Pic: the coconut-like Nypa (Nipah) swamp
    Nypa (or Nipah) palm swamp exists for over 70 millions years and it is one of the oldest forest types in the world. A large and well-preserved area of Nypa palm swamp grows around Abai, along the downriver of Kinabatangan River.
    nipah swamp
    Nypa forest is a swampy area with brackish water. Nobody wants to walk in Nypa forest, as its ground is muddy. Also, the number of mosquitoes there can suck your blood dry. Due to the semi-saline water and seasonal flood, very few plant and fruit species can flourish there. In short, Nypa swamp is a hostile environment to most animals. Egret, heron and wild boar go there sometimes, but they never call it home.
    orangutan moving in nypa palm
    It was a quiet morning. I was on a birdwatching tour with friends in mangrove and nypa zones of Kinabatangan wetland. Our small boat entered a tributary of Kinabatangan River and cruised slowly in dense forest of Nypa palm. Instead of bird’s chirping, we heard loud noise of rustling leaves. We looked at the direction of the sound and saw the palm leaves shaked violently. There was something moving inside, and it was big.
    orang-utan in nipah swamp
    The beast was moving slowly behind the Nypa palm along the river. We couldn’t see it, so we just followed the rustling leaves, hoping that it would show up near the river. After 10 minutes, our patience paid off and we saw it passed by a small opening between trees, for a few seconds. Affirmative, it’s an orangutan.
    orangutan eating nypa palm
    This orangutan stopped a few times to fall the palm trees. The palm is as big as my arm, and this orangutan could shake, bend then broke it easily. After crackling sounds of broken branch, there would be a long moment of silence, but we still could hear that it was munching something crunchy.
    orangutan eats nipah
    Our tour guide knew what it was eating. This orangutan was searching for the juicy core of the young Nypa palm. This is not the first time he sees orangutan in Nypa swamp, and he believes this is not the only orangutan active here. Behind the Nypa swamp is a forested land, probably where the orangutan lives. Most of the time this orangutan was staying quite far behind the trees. It was only one time I could peep through the tree gaps and photographed it.
    orangutan climbing nypa palm
    The orangutan noticed us but not quite bothered about our presence. It just continued its food journey, almost breaking all the branches it grabbed. As mentioned, Nypa swamp is muddy and orangutan hates water, so it was climbing from tree to tree, to avoid getting wet in mud. Orangutan is smart. If it has to enter the water, it knows how to use stick to test the depth of water. Someone even saw orangutan eating fish. Probably orangutan knows how to fish too, LOL.
    adult orangutan in Kinabatangan
    You can tell this orangutan is an adult by looking at its cheek pads called flanges. Unlike other primates, orangutan is a solitary animal and spends most of the time alone.
    Below are more photos for your viewing pleasure. Such unusual scene and behavior are not something we see every day.
    orangutan in nypa forest
    orangutan in nipah swamp
    Normal tourists seldom visit this area so we have the cool view all for ourselves. ðŸ™‚
    orangutan on nypa palm tree
    orangutan in the swamp
    orangutan on nipah
    We saw other damaged Nypa palm next to the river and believed these are done by orangutan.
    nypa palm eaten by orangutan
    broken nipah
    No doubt it was an interesting encounter. However, I’m very curious that why orangutan hunts for food in Nypa palm. Is it because orangutan can’t find enough food in rainforest nearby, or it loves the taste of Nypa palm? I wonder..
    Photos taken in Sandakan, Sabah, Malaysia Borneo

    For further information log on website :
    http://www.mysabah.com/wordpress/orangutan-in-the-swamp/

    Advantages and Disadvantages of Fasting for Runners

    Author BY   ANDREA CESPEDES  Food is fuel, especially for serious runners who need a lot of energy. It may seem counterintuiti...