Litterfall and nutrients return in Nothofagus antarctica forests growing in a site quality gradient with different management uses in Southern Patagonia

The use of dominant heights for the estimation of site index is compared with the use of the average of dominant and codominant heights. Data collected on the University Research Forest are presented to illustrate the variability in tree heights and diameters within the two upper crown classes in well-stocked stands of immature Douglas fir.HeightIt is shown that the use of dominant heights reduces considerably the number of measurements required for a site index determination of given accuracy. Minimum sample sizes are given for three limits of accuracy for use in different site qualities. A general field and office procedure is outlined for the determination of minimum sample size in stands other than those described.DiameterThe use of diameter in site determination is discussed. Site indices based on the height of the tree of mean diameter, the height of the tree of mean basal area, and mean height are compared.ConclusionsQuick estimates of site quality can best be obtained by the measurement of total height of sample dominant trees, selected at random. For this purpose, tables are presented which list the average height of dominant trees by age and site classes for use in stands of Douglas fir, and western hemlock, respectively.

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Water Quality Controls in Construction

1st Water Quality, Drought, Human Health and Engineering Conference ◽

10.1115/water2006-20020 ◽

2006 ◽

Author(s):

Claude J. Wookey

Keyword(s):

Water Quality ◽

Quality Control ◽

Human Exposure ◽

Water Discharge ◽

The United States ◽

Site Quality ◽

Construction Sites ◽

Water Quality Control ◽

Preventative Measure ◽

A Site

Water Quality control for construction sites is a requirement at any site within the United States. Erosion Controls are the first, and many times, last preventative measure for water discharge from a site. If these fail, streams, wetlands, or even off-site upland areas (yards, etc.) are adversely affected. Site quality is affected when valuable soil is lost and restoration requires replacement. Human exposure to contaminants, violation of governmental regulations, contractor reputation, and the overall economics involved in construction are at risk.

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Proposals for Nothofagus antarctica diameter growth estimation: simple vs. global models

Journal of Forest Science ◽

10.17221/22/2014-jfs ◽

2014 ◽

Vol 60 (No. 8) ◽

pp. 307-317 ◽

Cited By ~ 5

Author(s):

H. Ivancich ◽

G.J. Martínez Pastur ◽

M.V. Lencinas ◽

J.M. Cellini ◽

P.L. Peri

Keyword(s):

Tree Growth ◽

Growth Models ◽

Site Quality ◽

Diameter Growth ◽

Wide Range ◽

Nothofagus Antarctica ◽

Simple Growth ◽

Simple Equations ◽

Diameter Growth Models ◽

Stand Conditions

Tree growth is one of the main variables needed for forest management planning. The use of simple models containing traditional equations to describe tree growth is common. However, equations that incorporate different factors (e.g. site quality of the stands, crown classes of the trees, silvicultural treatments) may improve their accuracy in a wide range of stand conditions. The aim of this work was to compare the accuracy of tree diameter growth models using (i) a family of simple equations adjusted by stand site quality and crown class of trees, and (ii) <br /> a unique global equation including stand and individual tree variables. Samplings were conducted in 136 natural even-aged Nothofagus antarctica (Forster f.) Oersted stands in Southern Patagonia (Argentina) covering age (20–200 years), <br /> crown class and site quality gradients. The following diameter growth models were fitted: 16 simple equations using two independent variables (age and one equation for each stand site quality or crown class) based on Richards model, plus a unique global equation using three independent variables (age, stand site quality and crown class). Simple equations showed higher variability in their accuracy, explained between 54% and 92% of the data variation. The global model presented similar accuracy like the better equations of the simple growth models. The unification of the simple growth models into a unique global equation did not greatly improve the accuracy of estimations, but positively influenced the biological response of the model. Another advantage of the global equation is the simple use under a wide range of natural stand conditions. The proposed global model allows to explain the tree growth of N. antarctica trees along the natural studied gradients.    

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Distribution of the radiative index of dryness and forest site quality in a mountainous watershed

Canadian Journal of Forest Research ◽

10.1139/x84-128 ◽

1984 ◽

Vol 14 (5) ◽

pp. 717-721 ◽

Cited By ~ 5

Author(s):

S. J. Tajchman

Keyword(s):

Complex Terrain ◽

Forest Biomass ◽

Aridity Index ◽

Site Quality ◽

Seasonal Effects ◽

Forest Site ◽

Net Radiation ◽

Energy Exchanges ◽

A Site

The radiative aridity index, β (i.e., the ratio of yearly sums of net radiation to those of the latent heat of precipitation), and forest biomass were obtained for 245 terrain segments [Formula: see text] in an Appalachian watershed. A hypothesis was tested that β can be used as a site quality indicator in complex terrain. Regression analysis yielded the following relationship between the average forest biomass of the watershed (Mo = 15.94 kg m−2), the biomass (Mi), the radiative aridity index (βi), and the azimuth (Ai) of terrain segments: Mi/M0 = 2βi[l−Ai/2π + (Ai/2π)4] ± 0.27. The value of the expression in the bracket reaches its maximum for Ai = 0 (north facing slopes), and a minimum for Ai = 227° (southwest facing slopes). A possible interpretation of the obtained relationship is that p represents long term (e.g., daily and seasonal) effects of water and energy exchanges of terrain segments on growth, and the expression in the bracket represents the aspect-related effects of daily fluctuations of microclimate of terrain segments on growth.

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Regeneration in a Pole-Stage Forest of Eucalyptus regnans Subjected to Different Fire Intensities in 1982

Australian Journal of Botany ◽

10.1071/bt9960393 ◽

1996 ◽

Vol 44 (4) ◽

pp. 393 ◽

Cited By ~ 35

Author(s):

DH Ashton ◽

DG Martin

Keyword(s):

Soil Seed Bank ◽

Initial Density ◽

Site Quality ◽

First Year ◽

Adjacent Area ◽

Eucalyptus Regnans ◽

Species Dominance ◽

Vegetative Regeneration ◽

Seed Regeneration ◽

A Site

In 1982, fire burnt stands of Eucalyptus regnans F.Muell. in a relatively dry site in Victoria. In one area, the fire killed both canopy and understorey; in an adjacent area, only understorey was destroyed. Regeneration in the two areas was similar over the following year, but diverged thereafter to produce understoreys with different species dominance. In both stands, a poor supply of mature E. regnans seed in the crowns at the time of the fire resulted in relatively low initial density of seedlings: in the firekilled stand, this meant that closure of the canopy of the stratum was delayed for 5 or 6 years; however, in the understorey-killed stand, none of the E. regnans seedlings survived for 2 years. The soil seed bank was reduced more severely in the fire-killed than in the understorey-killed stand, although not all seed germinated in the first year. Vegetative regeneration of herbs and shrubs occurred from shallower layers of soil in the understorey-killed than in the fire-killed stand. An increase in soil fertility after the fire, as measured by seedling bioassay, was apparent only in the first season after the fire and was correlated with higher levels of available P. In the understorey-killed stand, fertility in the topsoil was greater than that in the fire-killed stand, and growth in diameter at breast height of dominant trees was significantly greater than in adjacent unburnt stands in the first few years after the fire. By comparison, when fire burnt through a site of higher rainfall after the maturation of the current crop of canopy-stored seed, regeneration was initially denser and growth considerably greater than that in the drier site. The study demonstrated that the course of secondary succession depends on site quality, timing of the fire in relation to seed production, soil seed germination, vegetative growth from protected organs, the severity of the fire, the presence or absence of browsing, and, in the long term, the frequency of recurrent fire.

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A site quality model for blackbutt (Eucalyptus PilularisSmith)

Australian Forestry ◽

10.1080/00049158.1995.10674640 ◽

1995 ◽

Vol 58 (2) ◽

pp. 31-34

Author(s):

Spencer Bruskin

Keyword(s):

Site Quality ◽

Quality Model ◽

A Site

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Tree health influences diameter growth along site quality, crown class and age gradients in Nothofagus forests of southern Patagonia

Journal of Forest Science ◽

10.17221/30/2013-jfs ◽

2013 ◽

Vol 59 (No. 8) ◽

pp. 328-336 ◽

Cited By ~ 2

Author(s):

H. Attis Beltrán ◽

G. Martínez Pastur ◽

H. Ivancich ◽

M.V. Lencinas ◽

L.M. Chauchard

Keyword(s):

Carbon Stocks ◽

Site Quality ◽

Tree Age ◽

Diameter Growth ◽

Nothofagus Pumilio ◽

Tree Health ◽

Qualitative Variable ◽

Diameter Increment ◽

Southern Patagonia ◽

Nothofagus Forests

We examined the influence of tree health on annual diameter increment of trees along gradients in stand site quality, crown classes and tree age in Nothofagus pumilio forests of Southern Patagonia. Healthy trees had higher annual diameter increment than unhealthy trees along all gradients (site quality, crown class, tree age). We argue that tree health could be employed as a qualitative variable in models of tree growth to estimate aboveground biomass and carbon stocks in this forest system.  

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