Predicting long-term sapling dynamics and canopy recruitment in northern hardwood forests

2011 ◽  
Vol 41 (5) ◽  
pp. 903-919 ◽  
Author(s):  
Jacob J. Hanson ◽  
Craig G. Lorimer ◽  
Corey R. Halpin
Keyword(s):  
Growth Rates ◽  
Forest Composition ◽  
Calibration Data ◽  
Gap Size ◽  
Tree Model ◽  
Individual Tree ◽  
Northern Hardwood ◽  
Wide Range ◽  
Sapling Density

Prediction of forest composition and structure over multiple generations of trees is often hampered by limited data on understory tree dynamics and the highly variable process of canopy recruitment in forest openings. In this paper, we describe a model of sapling dynamics and overstory recruitment for CANOPY, a spatially explicit, crown-based, individual-tree model of gap dynamics. The model incorporates gap size as a predictor of sapling recruitment and height growth, and it mimics the processes of sapling release, gap capture, and lateral gap closure. Calibration data were derived from 12 data sets with a wide range of stand ages and disturbance history in northern hardwood stands in the Great Lakes region, USA. The model accounted for 30%–62% of the variation in sapling density, composition, and growth rates. Predicted effects of increasing gap size on growth rate were similar to observed trends. Growth equations that included gap size as an independent variable generally gave better predictions of sapling density, species composition, and growth rates than equations based on conventional plot-level competition metrics. Long-term, 1000-year simulations produced estimates of stand basal areas and tree density in each size class that are close to the mean observed values for old-growth stands in the region.

scholarly journals Sugar Maple Height-Diameter and Age-Diameter Relationships in an Uneven-Aged Northern Hardwood Stand

1999 ◽  
Vol 16 (1) ◽  
pp. 43-47 ◽  
Author(s):  
Laura S. Kenefic ◽  
Ralph D. Nyland
Keyword(s):  
New York ◽  
Growth Rates ◽  
Acer Saccharum ◽  
Sugar Maple ◽  
Structural Complexity ◽  
Selection System ◽  
Northern Hardwood ◽  
Wide Range ◽  
Central New York ◽  
Growing Conditions

Abstract Sugar maple (Acer saccharum Marsh.) height-diameter and age-diameter relationships are explored in a balanced uneven-aged northern hardwood stand in central New York. Results show that although both height and age vary considerably with diameter, these relationships can be described by statistically valid equations. The age-diameter relationship compares favorably to one reported by Tubbs (1977) for sugar maple in unmanaged (virgin) northern hardwoods, suggesting that periodic cuttings improved growing conditions in our stand. Deliberate attempts to control size-class distribution and tree spacing should continue to increase diameter growth rates and decrease the time needed to reach certain threshold tree sizes. Growth rates that can be reasonably expected in this and similarly structured stands are provided. Lastly, a wide range of heights and diameters are documented, confirming the structural complexity associated with the balanced selection system. An equation to predict sugar maple height from diameter is provided and may prove useful when assessing habitat or visual characteristics of complex uneven-aged stands. North. J. Appl. For. 16(1):43-47.

CryoSat SIRAL: calibration and achievable performance after ten years of operations

2020 ◽  
Author(s):  
Michele Scagliola ◽  
Marco Fornari ◽  
Marco Meloni ◽  
Jerome Bouffard ◽  
Tommaso Parrinello
Keyword(s):  
Transfer Function ◽  
Phase Difference ◽  
Ocean Surface ◽  
Calibration Data ◽  
Path Delay ◽  
Radar Altimeter ◽  
Angle Of Arrival ◽  
True Value ◽  
Wide Range

<p>The main payload of CryoSat is a Ku-band pulsewidth limited radar altimeter, called SIRAL (Synthetic interferometric radar altimeter), that is equipped with two antennas for single-pass interferometric capability.</p><p>Due to the unique characteristics of SIRAL, a proper calibration approach was developed. In fact, not only corrections for transfer function, gain and instrument path delay have to be computed (as in previous altimeters), but also corrections for phase (SAR/SARIn) and phase difference between the two receiving chains (SARIN only). To summarize, SIRAL performs regularly four types of internal calibrations:</p><p>-           CAL1 in order to calibrate the internal path delay and long-term power drift.</p><p>-           CAL2 in order to compensate for the instrument IF transfer function.</p><p>-           CAL4 to calibrate the interferometer.</p><p>-           AutoCal, a specific sequence used to calibrate the gain and phase difference for each AGC setting.</p><p>After about 10 years of operational activity of the CryoSat satellite, the performance of the SIRAL instrument are revealed to be in line or better than the expected one.</p><p>In fact the calibration products, that have been designed to model a wide range of imperfections of the instrument, can be analyzed to highlight whether and how the instrument is changing over the time also as function of its thermal status. It is worth underlining here that each variation of the instrument measured by the calibration data is compensated in the Level1 processing. Inspecting the temporal evolution of the calibration data, SIRAL has been verified to be stable during its life. The performance of the SIRAL will be presented together with the outcomes of the stability analysis on the calibration data, in order to verify that the instrument has reached the requirements and that it is maintaining the performance over its life.</p><p> </p><p>In order to monitor the performance of the CryoSat interferometer along the mission, in orbit calibration campaigns have been periodically performed about once a year. The end-to-end calibration strategy for the CryoSat interferometer uses the ocean surface as the known external target. In fact, the interferometer can be used to determine the across-track slope of the overflown surface and the slope of the ocean surface can be considered as known starting from the geoid. Denoting by β the across-track slope of the ocean and assuming that the knowledge error of the geoid slope is negligibly small, β can be compared with the across-track slope derived from CryoSat SARin Level1b products which results in β'=η(θ-χ) where η is a geometric factor, θ is the angle of earliest arrival measured by the CryoSat interferometer and χ is the baseline roll angle. By comparison of the expected across-track slope β and the measured across-track slope β', the accuracy and the precision of the angle of arrival θ measured by the CryoSat interferometer can be assessed.</p><p>In our analysis, the long-term accuracy (i.e. the closeness of the measurement to the true value) and the long-term precision (i.e. the closeness of agreement among a set of measurements) of the CryoSat interferometer have been assessed.</p>

Effects of organic matter removal, soil compaction, and vegetation control on 5-year seedling performance: a regional comparison of Long-Term Soil Productivity sites

2006 ◽  
Vol 36 (3) ◽  
pp. 529-550 ◽  
Author(s):  
Robert L Fleming ◽  
Robert F Powers ◽  
Neil W Foster ◽  
J Marty Kranabetter ◽  
D Andrew Scott ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Compaction ◽  
Forest Floor ◽  
Soil Productivity ◽  
Individual Tree ◽  
Seedling Performance ◽  
Organic Matter Removal ◽  
Vegetation Control ◽  
Wide Range

We examined fifth-year seedling response to soil disturbance and vegetation control at 42 experimental locations representing 25 replicated studies within the North American Long-Term Soil Productivity (LTSP) program. These studies share a common experimental design while encompassing a wide range of climate, site conditions, and forest types. Whole-tree harvest had limited effects on planted seedling performance compared with the effects of stem-only harvest (the control); slight increases in survival were usually offset by decreases in growth. Forest-floor removal improved seedling survival and increased growth in Mediterranean climates, but reduced growth on productive, nutrient-limited, warm–humid sites. Soil compaction with intact forest floors usually benefited conifer survival and growth, regardless of climate or species. Compaction combined with forest-floor removal generally increased survival, had limited effects on individual tree growth, and increased stand growth in Mediterranean climates. Vegetation control benefited seedling growth in all treatments, particularly on more productive sites, but did not affect survival or alter the relative impact of organic matter removal and compaction on growth. Organic matter removal increased aspen coppice densities and, as with compaction, reduced aspen growth.

Is everything all right up there? A long-term interdisciplinary silvicultural systems project in a high elevation fir-spruce forest at Sicamous Creek, B.C.

1999 ◽  
Vol 75 (3) ◽  
pp. 467-472 ◽  
Author(s):  
Alan Vyse
Keyword(s):  
British Columbia ◽  
High Elevation ◽  
Wildlife Habitat ◽  
Spruce Forest ◽  
Individual Tree ◽  
Subalpine Fir ◽  
Engelmann Spruce ◽  
South Central ◽  
Wide Range

The Sicamous Creek Project was established as part of the British Columbia Provincial Silvicultural Systems program in 1990 to investigate the effects of clearcutting and other practices on a high elevation forested ecosystem. The objective is to provide the forestry community with information on the ecology of high elevation forests in the Southern Interior, and the probable responses to a wide range of disturbance. After a period of planning by a team of scientists and foresters from several agencies, a site in subalpine fir-Engelmann spruce forest at 1530 m to 1830 m elevation near the town of Sicamous in the south central interior of British Columbia was logged in the winter of 1994–95. A range of treatments was created by logging one third of the forest in 30 ha experimental units using a range of opening sizes (individual tree selection, 1/10 ha, 1 ha, and 10 ha) and a no-logging control. Within these experimental units, smaller areas (0.08 ha) have been treated to create a range of soil disturbance conditions (no disturbance, burning, complete organic soil removal, mounding). A wide range of studies has been conducted on the site by a team of scientists before and after treatment and those studies are continuing. The project is long-term, (at least 30 years), the main treatments are sufficiently large to have operational significance, and the supported studies are intended to be interdisciplinary in scientific method and scope. Support for the project is strong within the operational forestry community because information on logging costs, safety issues and snags, windthrow, bark beetle management, wildlife habitat and small streams has already been made available to them. Studies of stand structure and wildlife habitat suggest that in future much greater emphasis should be placed on the silviculture of fir than spruce. Key words: silviculture systems, clearcutting, opening size, Engelmann spruce, subalpine fir, long term research, interdisciplinary research

Time Series and Postglacial Forest Ecology

1981 ◽  
Vol 15 (3) ◽  
pp. 265-277 ◽  
Author(s):  
David G. Green
Keyword(s):  
Time Series ◽  
Forest Ecology ◽  
Forest Succession ◽  
Fire Frequency ◽  
Forest Composition ◽  
Mixed Composition ◽  
Individual Tree ◽  
Tree Communities ◽  
Pollen Records

AbstractForest ecology suffers from a lack of long-term community records. Preserved pollen data are richer in such information than is generally realized. By applying suitable statistical techniques to pollen records, one can learn much about competition, succession, and population dynamics in past tree communities. In this study, preserved pollen records from Everitt Lake, Nova Scotia, are analyzed as time series. Time domain studies reveal the post-fire responses of individual tree taxa. Correlograms yield models of past forest succession patterns. The models explain some effects of changing fire frequency, thus suggesting mechanisms by which fire, competition, and climate combine to produce long-term forest composition changes. Frequency domain studies suggest relationships between disturbance cycles, stand composition, and forest mosaics. Fire frequencies are seen to be highest where fire-dependent species abound and most regular where tree stands have uniform, not mixed, composition.

Effects of Long-Term Preconditioning on Growth and Flowering of Some Snow Tussock (Chionochloa Spp.) Populations in Otago, New Zealand

1979 ◽  
Vol 27 (5) ◽  
pp. 617 ◽  
Author(s):  
DH Greer
Keyword(s):  
New Zealand ◽  
Growth Rates ◽  
Threshold Temperature ◽  
Critical Threshold ◽  
Physiological Plasticity ◽  
Subsequent Growth ◽  
Wide Range ◽  
Flowering Behaviour ◽  
High Degree

Clone members of each of three altitudinal populations (910-1590 m) of two ecologically important snow tussocks (Chionochloa macra and C. rigida) reciprocally transplanted to four sites (10-1590 m) in 1960 were further subdivided and re-reciprocally transplanted to the same four sites in 1974 and their subsequent growth and flowering behaviour followed over two seasons. Interpopulation differences in stature and growth rates remained distinct after the 14-year intervening period, reinforcing earlier evidence for some genetic control of these characters. In contrast, the flowering of each population at each site had converged towards that of the resident plants, which indicated some adjustment to the critical threshold temperature for flowering. Interpopulation differences in flowering behaviour could not, therefore, be strictly controlled genetically as had been previously assumed. No interpopulation differences emerged as a result of 14 years of preconditioning in diverse environments. Furthermore, the preconditioning had a negligible effect on the subsequent perfor- mance of each population in a wide range of temperature environments. Distinct differences in growth rates between a lowland coastal population of C. rigida and its alpine counterparts appear adaptive, suggesting differentiation of a lowland ecotype. The high degree of physiological plasticity inherent in all populations of snow tussock studied may have its origin in the climatically diverse post-Pleistocene period when genotypes with maximum flexibility may have been selected preferentially. Since then, probably as a result of expansion of snow tussock grasslands within the last millenium, local adaptive variants have evolved.

Relationships between growth, quality, and stocking within managed old-growth northern hardwoods

2012 ◽  
Vol 42 (6) ◽  
pp. 1115-1125 ◽  
Author(s):  
Chris Gronewold ◽  
Anthony W. D’Amato ◽  
Brian J. Palik
Keyword(s):  
Growth Dynamics ◽  
Quality Development ◽  
Old Growth ◽  
Individual Tree ◽  
Upper Peninsula ◽  
Northern Hardwood ◽  
Tree Quality ◽  
Upper Peninsula Of Michigan ◽  
Level Production

An understanding of long-term growth dynamics is central to the development of sustainable uneven-aged silvicultural systems for northern hardwood forests in eastern North America. Of particular importance are quantitative assessments of the relationships between stocking control and long-term growth and quality development. This study examined these relationships in a long-term silviculture experiment established in northern hardwood stands in the Upper Peninsula of Michigan, USA. Stands were old growth at the onset of the experiment and were maintained at three residual stocking levels (11.5, 16.1, and 20.7 m2·ha–1) over a 57-year period. Several aspects of long-term stocking control were evaluated, including the effects of residual stocking on tree quality development and the relationships between stand stocking and individual tree growth and stand-level production. Results suggest that residual stocking had little impact on quality development, likely due to the initial old-growth condition of the stands examined. In contrast, our results indicate that a range of stand densities will maintain acceptable rates of stand-level production in selection systems and that growth can be shifted between diameter classes depending on desired future stand conditions.

The Reproduction Vector of the Russian Economy: 1999-2007

2008 ◽  
pp. 94-109 ◽  
Author(s):  
D. Sorokin
Keyword(s):  
Economic Policy ◽  
Human Capital ◽  
Growth Rates ◽  
Developed Countries ◽  
Gdp Per Capita ◽  
Real Sector ◽  
Russian Economy ◽  
Per Capita ◽  
The Developed Countries

The problem of the Russian economy’s growth rates is considered in the article in the context of Russia’s backwardness regarding GDP per capita in comparison with the developed countries. The author stresses the urgency of modernization of the real sector of the economy and the recovery of the country’s human capital. For reaching these goals short- or mid-term programs are not sufficient. Economic policy needs a long-term (15-20 years) strategy, otherwise Russia will be condemned to economic inertia and multiplying structural disproportions.

Modern prevention and active longevity programs on the basis of disruptive domestic technologies: positive experience and prospects for application

2020 ◽  
pp. 66-73
Author(s):  
A. Simonova ◽  
S. Chudakov ◽  
R. Gorenkov ◽  
V. Egorov ◽  
A. Gostry ◽  
...  
Keyword(s):  
Personalized Medicine ◽  
Early Detection ◽  
Laboratory Diagnostics ◽  
Positive Experience ◽  
Practical Application ◽  
Wide Range ◽  
Integrated Program ◽  
Long Term Experience ◽  
Early Detection And Prevention

The article summarizes the long-term experience of practical application of domestic breakthrough technologies of preventive personalized medicine for laboratory diagnostics of a wide range of socially significant non-infectious diseases. Conceptual approaches to the formation of an integrated program for early detection and prevention of civilization diseases based on these technologies are given. A vision of the prospects for the development of this area in domestic and foreign medicine has been formed.

To the 70th anniversary of World Meteorological Organization. Scientific and technical cooperation of Hydrometeorological Center of the USSR/Russia in the Programs of World Meteorological Organization

2020 ◽  
pp. 117-138
Author(s):  
S.V. Borshch ◽  
◽  
R.M. Vil’fand ◽  
D.B. Kiktev ◽  
V.M. Khan ◽  
...  
Keyword(s):  
Environmental Monitoring ◽  
High Efficiency ◽  
World Meteorological Organization ◽  
70Th Anniversary ◽  
Technical Level ◽  
Technical Cooperation ◽  
Wide Range

The paper presents the summary and results of long-term and multi-faceted experience of international scientific and technical cooperation of Hydrometeorological Center of Russia in the field of hydrometeorology and environmental monitoring within the framework of WMO programs, which indicates its high efficiency in performing a wide range of works at a high scientific and technical level. Keywords: World Meteorological Organization, major WMO programs, representatives of Hydrometeorological Center of Russia in WMO

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