The impact of tree and stand characteristics on spruce beetle (Coleoptera: Scolytidae) induced mortality of white spruce in the Copper River Basin, Alaska

2004 ◽  
Vol 34 (4) ◽  
pp. 810-816 ◽  
Author(s):  
Patricia Doak
Keyword(s):  
Growth Rate ◽  
River Basin ◽  
Basal Area ◽  
Stand Density ◽  
White Spruce ◽  
Study Region ◽  
Individual Traits ◽  
Spruce Beetle ◽  
The Individual ◽  
The Impact

I examined the relationships between individual and stand-level characteristics of white spruce, Picea glauca (Moench) Voss, and the incidence of spruce beetle, Dendroctonus rufipennis Kirby, induced mortality. The study region, in the Kennicott Valley of the Copper River Basin, Alaska, has contained an active spruce beetle epidemic since 1989. I investigated the relationship among the individual traits of host age, size (diameter at breast height, DBH), and growth rate (basal area increment, BAI) and mortality from the spruce beetle. I also examined the effects of stand density, mean DBH, and mean BAI on percent mortality within plots. Survival was higher for younger, smaller, and faster-growing trees. However, the effect of age is not significant when included in a logistic regression model examining the effect of individual host traits on host survival. Mortality increased with increasing DBH and decreasing BAI, and there was a significant interaction between DBH and BAI. While the proportion of individuals killed by the spruce beetle significantly differed between stands, I found no significant relationships between stand-level characteristics and mortality rate. This research suggests that the individual traits of host size and growth rate, as well as their interaction are the best predictors of susceptibility to spruce beetle-induced mortality in this system.

The Impact of Browsing Animals on the Stand Dynamics of Monotypic Mountain Beech (Nothofagus solandri) Forests in Canterbury, New Zealand

1994 ◽  
Vol 42 (2) ◽  
pp. 113 ◽  
Author(s):  
GT Jane
Keyword(s):  
New Zealand ◽  
Cervus Elaphus ◽  
Basal Area ◽  
Stand Density ◽  
Natural Disturbance ◽  
Basic Relationship ◽  
Basic Parameters ◽  
The 1960S ◽  
Logarithmic Relationship ◽  
The Impact

Mountain beech is frequently the sole canopy species in the montane forests of Canterbury, New Zealand and often the only significant tree or shrub present over large areas and this allows examination of a very simple ecosystem. Data from remeasurement of over 400 permanent quadrats in six areas are examined to elucidate the impact of browsing animals on natural processes. The changes in basic parameters such as stand density and basal area over a decade form consistent patterns in both visual and statistical techniques and this allows identification of important quadrats for detailed study. The basic relationship between density and basal area follows well an established semi-logarithmic relationship, even in decade by decade changes on individual quadrats. Deviations in this pattern can be related to natural disturbance events. The impact of browsing animals, mainly red deer (Cervus elaphus) varied between the different areas. Although numbers peaked in the 1930s and 1940s and declined through commercial hunting in the 1960s-1980s, the impact on the vegetation remains and will persist for many decades.

Effect of competition on individual white spruce production in young boreal mixedwood forests

2020 ◽  
Vol 50 (8) ◽  
pp. 726-735
Author(s):  
Sandra Carr ◽  
Guy R. Larocque ◽  
Nancy Luckai ◽  
F. Wayne Bell
Keyword(s):  
Growth Rate ◽  
Relative Growth Rate ◽  
Production Efficiency ◽  
Basal Area ◽  
Tree Height ◽  
White Spruce ◽  
Structural Features ◽  
Relative Growth ◽  
Mixedwood Forests ◽  
Competition Indices

Increasing the production of wood fibre from conifer species such as white spruce (Picea glauca (Moench) Voss) is one of many challenges in the management of boreal mixedwood forests. The effects of various competition measures on relative growth and relative growth rate variables were calculated for individual white spruce subject trees. Correlation analysis was used to explore relationships with competitor structural features, including the ratio of competitor basal area to subject tree basal area (CBAS), the ratio of competitor height to subject tree height (AHCS), and the proportion of softwood (FSW). Regression analysis was used to explore relationships with three distance-dependent competition indices. The ratio of subject tree height to diameter at breast height (DBH) (HDR), crown ratio (CR), and crown relative increment rate (CRIR) were significantly correlated with CBAS and AHCS. HDR, CR, CRIR, and DBH relative growth rate were all statistically significantly related to the competition indices. Results indicated that (i) relative growth and relative growth rate measures successfully captured a range of competition, (ii) crowns of trees with larger diameters used their horizontal growing space more efficiently to produce stemwood, and (iii) the proportion of softwood contributing to competition did not appear to influence subject tree production efficiency. Growth efficiency variables have the potential to improve our understanding of boreal mixedwood dynamics.

Mortality of white spruce during a spruce beetle outbreak on the Kenai Peninsula in Alaska

1983 ◽  
Vol 13 (1) ◽  
pp. 96-101 ◽  
Author(s):  
Richard A. Werner ◽  
Edward H. Holsten
Keyword(s):  
White Spruce ◽  
Permanent Plots ◽  
Kenai Peninsula ◽  
South Central ◽  
Creek Watershed ◽  
Spruce Beetle ◽  
Spruce Stands ◽  
Long Term Impact ◽  
The Impact

White spruce (Piceaglauca (Moench) Voss) stands in the Resurrection Creek watershed in south-central Alaska were infested by spruce bettles, Dendroctonusrufipennis Kirby, between 1974 and 1975. Thirty permanent plots were established within the infested area in 1976 to evaluate the immediate and long-term impact on white spruce stands. Plots were revisited annually for 5 years. Between 1976 and 1980, 29% of all white spruce was killed by spruce beetles. This loss accounted for 59% of the commercial white spruce volume in the watershed. Mortality was greatest in the larger diameter classes during the early part of the infestation, but smaller diameter trees were subsequently attacked as the number of noninfested trees declined. The impact of spruce beetles on structure and species composition of white spruce stands is given along with a discussion of management implications.

Assessing the production and the impact of cultivated oysters in the Thau lagoon (Mediterranee, France) with a population dynamics model

2001 ◽  
Vol 58 (5) ◽  
pp. 1012-1020 ◽  
Author(s):  
A Gangnery ◽  
C Bacher ◽  
D Buestel
Keyword(s):  
Growth Rate ◽  
Population Dynamics ◽  
Standing Stock ◽  
Individual Growth ◽  
Economic Activities ◽  
Daily Growth ◽  
Mediterranean Mussel ◽  
Thau Lagoon ◽  
The Individual ◽  
The Impact

The Thau lagoon (France) has been studied for many years because of its ecological interest related to economic activities: shellfish cultivation, tourism, and industry. The standing stock of cultivated filter feeders is around 20 000 t and consists of two main species, the Japanese oyster Crassostrea gigas and the Mediterranean mussel Mytilus galloprovincialis. To predict changes in the standing stock and the annual production, a mathematical model of the population dynamics was defined. It was based on the continuous equation of the density as a function of the mortality rate, the individual growth rate, and the interindividual variability. The daily growth rate was derived from field surveys and depended on the phytoplankton concentration and individual weight. The model also took into account the rearing strategy of the producers defined by the timetable of seeding and harvesting, obtained by an inquiry among the producers and used to simulate real cases of standing stock changes. The model was also used to assess the potential impact on the environment through the computation of the food consumption, which was compared with the residence time and the primary production.

scholarly journals Coupe préparatoire et croissance en surface terrière d'une sapiniére de seconde venue à la forêt modèle du Bas-Saint-Laurent, Québec

2001 ◽  
Vol 77 (4) ◽  
pp. 685-695 ◽  
Author(s):  
Richard Zarnovican ◽  
Jean-Martin Lussier ◽  
Claude Laberge
Keyword(s):  
Growth Rate ◽  
Relative Size ◽  
Basal Area ◽  
Balsam Fir ◽  
Basal Area Growth ◽  
Periodic Growth ◽  
Area Growth ◽  
Crown Characteristics ◽  
Highly Correlated ◽  
The Impact

Balsam fir basal area growth was studied 5 years after the preparatory cut in the context of natural regeneration by the shelterwood system. The study was carried out in a 60-year-old second-growth balsam fir-yellow birch stand. The felling trials were realized in 16 plots and consisted of control and three felling regimes (15, 30 and 45% of removed basal area). The periodic (5 years) mean growth rate on dbh of trees in plots varies between 6 and 12% in response to felling intensity. The basal area of plots presents a mean periodic growth rate of 7.4% independently of felling intensity. There are highly significant correlations between the live crown characteristics and periodic basal area growth. This growth is highly correlated with inital diameter and intensity of felling. The trees of higher relative size are more productive than the others and the impact of felling on periodic basal area growth is significant when the intensity of felling is greater than 30%. Conversely, the ratio between periodic basal area growth after treatment and periodic basal area growth before treatment is correlated only with the intensity of felling. Finally, intensity of felling had no effect on periodic basal area growth per square meter of crown projected area. Key words: preparatory felling, basal area growth, balsam fir

scholarly journals THE IMPACT OF HUMAN FACTORS ON THE CHANGE IN VEGETATION COVER OF THE BE RIVER BASIN IN THE PERIOD FROM 2000 TO 2015

2020 ◽  
Vol 15 (9) ◽  
pp. 53
Author(s):  
Phan Văn Trung ◽  
Nguyễn Thám
Keyword(s):  
Growth Rate ◽  
Human Factors ◽  
Population Growth ◽  
River Basin ◽  
Vegetation Cover ◽  
Population Growth Rate ◽  
Mapping Method ◽  
Rapid Urbanization ◽  
Set Up ◽  
The Impact

 The Be river basin is located in the area with a rapid urbanization rate and a large immigrants proportion annually. Therefore, the population growth rate for the period from 2000 to 2015 in the river basin is up 3,53% which is 3,27 times as high as the population growth rate of Vietnam. These are the major causes leading to the fluctuation in vegetation cover of the Be river basin during over time. This research used methodologies including data collection, statistical analysis, mapping method and geographic information system to evaluate the impact of human factors to the vegetation cover fluctuation of the Be river basin in the period from 2000 to 2015. Based on the results of change map in the vegetation cover, a research group set up fluctuating matrix, analyze to clarify the vegetation coverfluctuation situation due to human’s impacts in the Be river basin in the period from 2000 to 2015. 

scholarly journals Impact of Secondary Succession in the Xerothermic Grassland on the Population of the Eastern Pasque Flower (Pulsatilla patens)—Preliminary Studies

2021 ◽  
Vol 13 (22) ◽  
pp. 12575
Author(s):  
Monika Podgórska ◽  
Grzegorz Łazarski
Keyword(s):  
Secondary Succession ◽  
Permanent Plots ◽  
Strongly Correlated ◽  
Community Interest ◽  
Individual Traits ◽  
Number Of Leaves ◽  
The Individual ◽  
Pulsatilla Patens ◽  
The Impact ◽  
Number Of Individuals

We studied the impact of secondary succession in xerothermic grasslands on a population of Pulsatilla patens, a species of European Community interest. We established two permanent plots with a high number of individuals of P. patens in a xerothermic grassland in Southern Poland. We compared two areas, the first in open grassland (plot A), and the second with overgrowing vegetation (plot B). We assessed the population structure as well as the individual traits of the species. The total abundance of P. patens in the open xerothermic grassland was five times higher than in the overgrowing xerothermic grassland. A randomly clustering distribution was noted only in plot A; in plot B a random type of distribution occurred. The density structure of the rosettes was higher in plot A. The mean number of leaves in rosettes of P. patens as well as dimensions of intermediate stems and leaves of the species is strongly correlated with habitat conditions. The shadowing caused by shrubs and trees and high weeds observed in the overgrowing xerothermic grassland negatively impacted on the number of individuals, distribution, structure and morphology of P. patens.

scholarly journals Analysis of spatial correlation in predictive models of forest variables that use LiDAR auxiliary information

2017 ◽  
Vol 47 (6) ◽  
pp. 788-799 ◽  
Author(s):  
F. Mauro ◽  
V.J. Monleon ◽  
H. Temesgen ◽  
L.A. Ruiz
Keyword(s):  
Spatial Correlation ◽  
Linear Models ◽  
Auxiliary Information ◽  
Basal Area ◽  
Stand Density ◽  
Model Errors ◽  
Quadratic Mean ◽  
Quadratic Mean Diameter ◽  
Model Residuals ◽  
The Impact

Accounting for spatial correlation of LiDAR model errors can improve the precision of model-based estimators. To estimate spatial correlation, sample designs that provide close observations are needed, but their implementation might be prohibitively expensive. To quantify the gains obtained by accounting for the spatial correlation of model errors, we examined (i) the spatial correlation patterns of residuals from LiDAR linear models developed to predict volume, total and stem biomass per hectare, quadratic mean diameter (QMD), basal area, mean and dominant height, and stand density and (ii) the impact of field plot size on the spatial correlation patterns in a standwise managed Mediterranean forest in central Spain. For all variables, the correlation range of model residuals consistently increased with plot radius and was always below 60 m except for stand density, where it reached 85 m. Except for QMD, correlation ranges of model residuals were between 1.06 and 8.16 times shorter than those observed for the raw variables. Based on the relatively short correlation ranges observed when the LiDAR metrics were used as predictors, the assumption of independent errors in many forest management inventories seems to be reasonable and appropriate in practice.

scholarly journals Effect of Climate Variability on Green and Blue Water Resources in a Temperate Monsoon Watershed, Northeastern China

2021 ◽  
Vol 13 (4) ◽  
pp. 2193
Author(s):  
Junchao Jiang ◽  
Leting Lyu ◽  
Yuechi Han ◽  
Caizhi Sun
Keyword(s):  
Surface Water ◽  
Water Resources ◽  
River Basin ◽  
Water Resource ◽  
Green Water ◽  
Blue Water ◽  
Reference Period ◽  
Study Region ◽  
Green And Blue Water ◽  
The Impact

Over 80% of global grain production relies on green water, water from precipitation that is stored in unsaturated soil and supports plant growth. Blue water, precipitation that turns into surface water and groundwater, is also a vital surface water resource, and it can be directly utilized. The Tanghe River Basin is a typical temperate continental monsoon watershed in Northern China where residents and crops rely on blue and green water resources. In this study, the spatiotemporal distributions of water resources in the Tanghe River Basin were simulated using the soil and water assessment tool (SWAT) model for the period between 1970 and 2015. The results demonstrate that the Nash–Sutcliffe efficiency and coefficient of determination were both higher than 0.64 during the calibration and validation periods at all hydrological stations, indicating high simulation accuracy. The average annual water resources of the Tanghe River Basin are 759.37 mm. Green and blue water account for 68% and 32% of the total water resources, respectively. The study period was divided into the reference period (1970–1976) and the variation period (1977–2015), to explore the impact of climate change on the green and blue water resources of the Tanghe River Basin water resources. Compared with the reference period, the average green and blue water resources in the variation period decreased by 78.48 and 35.94 mm/year, and their rate changes were −13.45% and −13.17%, respectively. The water resource relative change rates were high in the south and low in the north, and they were predominantly affected by precipitation. This study improves our understanding of the hydrological processes as well as the availability of blue and green water in the study region, and can prove beneficial in promoting the sustainable development of small basins and the integrated watershed management in areas with similar climatic conditions.

scholarly journals Impact of Future Land-Use/Cover Change on Streamflow and Sediment Load in the Be River Basin, Vietnam

Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1244
Author(s):  
Dao Nguyen Khoi ◽  
Pham Thi Loi ◽  
Truong Thao Sam
Keyword(s):  
Land Use ◽  
River Basin ◽  
Agricultural Land ◽  
Sediment Load ◽  
Swat Model ◽  
Mitigation Strategies ◽  
Annual Streamflow ◽  
Study Region ◽  
Sustainable Water Resources Management ◽  
The Impact

Evaluation of the influence of land-use/cover (LUC) change on water and sediment fluxes from river basins is essential for proposing adaptation and mitigation strategies, but as of yet little information is available, especially in the tropics. For this motivation, the objective of this study was to assess the impact of scenarios of LUC change on streamflow and sediment load in the Be River Basin using the Dynamic Conversion of Land-Use and its Effects (Dyna-CLUE) model and the Soil and Water Assessment Tool (SWAT) model. The Dyna-CLUE and SWAT models were calibrated and validated against observed data in the period of 1980–2010. Three future LUC scenarios in 2030, 2050, and 2070 were generated utilizing the calibrated Dyna-CLUE model based on the historical conversion of forest land to agricultural land and urban area in the study region. Subsequently, the calibrated SWAT model was used to simulate the changes in streamflow and sediment load under these three future LUC scenarios. Results indicated that the annual streamflow and sediment load were estimated to be approximately 287.35 m3/s and 101.23 × 103 ton/month for the baseline period. Under the influence of future LUC scenarios, the annual streamflow and sediment load would experience increases of 0.19% to 0.45% and 0.22% to 0.68%, respectively. In addition, the 5th and 95th percentile values of streamflow and sediment load are predicted to rise in the context of future LUC change. The results achieved from the present study will support the managers and policy makers proposing appropriate solutions for sustainable water resources management and sediment control in the context of LUC change.

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