Institute of Forest
Centre for Ecological Research of Boreal Forests,
EVALUATION OF ACCURACY
OF SATELLITE TECHNIQUES
N. A. Abuschenko, D.
A. Altyncev, S. M. Semenov
This paper is concerned
with the main techniques for computer-aided processing of satellite imagery
from the NOAA satellite AVHRR instrument with the purpose of detecting
forest fires. Input data used in these methods are represented by values
of the physical quantities in the AVHRR channels: T3 - temperature in
channel 3, T4 - temperature in channel 4, T3 - T4 - temperature difference
in channel 3 and 4, and A1 and A2 - albedo in channel 1 and 2. The form
of the functions separating a class of fires and other objects represents
simple linear relations of form P > dp, where P is a current value
of the attribute (T3, T4, etc.), and dp is the threshold value of a given
attribute for a given class. The chief goal, when creating the classification
algorithm, is to seek an optimum threshold value for each attribute.
ESTIMATION OF EMISSION
AMOUNT OF BURNING PRODUCTS
N. A. Abuschenko, D.
A. Altyncev, S. A. Tashchilin, A. V. Tatarnikov
results for the period of April-October 1998 were used to estimate the
amount of emission of products of burning from forest fires on the territory
of Russia within 125░ - 145░ E. Burnt-out areas as a result of forest
fires were mapped using information from AVHRR channel 2 for the period
of observation covering spring and summer of 1999. In doing this, information
about the coordinates of fire pixels from real-time monitoring data was
used to update the location of burnt-out areas in channel 2 images. The
area deduced from these data totaled 6.8 million hectares.
THE SATELLITE SYSTEM
FOR REAL-TIME OBSERVATION OF FOREST FIRES
N. A. Abuschenko, D.
A. Altyncev, S. A. Tashchilin, A.V.Tatarnikov,
This paper is concerned
with the system for satellite real-time monitoring of forest fires that
has been created at the Institute of Solar-Terrestrial Physics SB RAS.
The main data used by the Center are represented by multispectral information
from the AVHRR radiometer installed on NOAA satellites. The satellite
information processing system that had been set up at the ISTP permits
ISTP researchers to solve a variety of problems related to assessment
of the state of forest resources involving primarily monitorings of the
fire and post-fire situation in the taiga area.
DENDROCHRONOINDICATION BY MEANS OF GAS ANALYSIS
B. G. Ageev1, V. D.
Nesvetailo2, Yu. N. Ponomarev 1, V. A. Sapozhnikova 1
The analysis of the
gas emitted from the wood of tree rings is suggested as an additional
characteristics of tree rings used in the dendrochronoindication research.
The wood of the rings of a scots pine (Pinus sylvestris L.) and Siberian
spruce (Picea obovata Ledeb.) is taken as an object of the investigations.
The wood samples are prepared by layer-by-layer careful separation of
the dry wood in year rings. The analysis of gas samples extracted under
vacuum from the wood was conducted with the help of the laser opto-acoustic
method. The experimental setup and measurement procedure are presented
in the report. It is found that the gas emitted from the tree samples
consists mainly of CO2 and its quantity correlates with the corresponding
ring width. The results of the experiments and prospects of the approach
suggested for the use in climate-ecological control are discussed.
NORWAY SPRUCE GROWTH
TRENDS IN LENINGRAD REGION
A. S. Alekseev, A. P.
Tree ring data, collected
from 81 sample plots regular distributed over all region territory were
used for Norway spruce growth trends analysis. The total number of sample
trees was 315, tree ring series cover a period from 1735 to 1995, in the
analysis 24 686 tree rings belonging to 6 age classes were used: 0-20
years old - 6300 tree rings, 21-40 - 6125, 41-60 - 5178, 61-80 - 3352,
81-100 - 1792, older than 100 - 1939. Tree ring data were grouped both
in age and size classes for removing age bias from the analysis, comparison
of rings width of trees which have appeared at the same age or at the
trees with the same diameter but in different calendar years gives a possibility
to remove completely age bias before analysis of growth trends. Generally
we may conclude that Norway spruce trees during the last decades show
increased growth for at least young and middle- aged generations.
GEOINFORMATION TECHNOLOGY OF SWAMP-FOREST STRUCTURE ANALYSIS USING SPACE IMAGES AND GROUND OBSERVATIONS
M. N. Alexeeva1, A.
G. Dukarev2, Yu. M. Polichtchouk1, N. N. Pologova2
Methodic problems of structure analysis are considered. Information technology of structure analysis of swamp-forest ecosystems on the basis of remote sensing data with geographic information system is supposed. Landscape areas typology is proposed for solving problems of analysis of forest-swamp ecosystems landscape structure in Vasugan territory. Technology developed is applied for processing high dimension space images above territory with using results of ground observations. Relative areas of various landscape areas are determined. The results are represented on landscape maps.
THE SOFTWARE PACKAGE
FOR PROCESSING SATELLITE DATA
D. A. Altyncev
The effectiveness of
the forest fire monitoring system (FFMS) using remotely sensed satellite
data (RSD) depends heavily on parameters of the software used. Standard
RSD processing packages have limited capabilities for setting up such
a system; therefore, for this purpose, the Space Monitoring Center operated
by the ISTP, Irkutsk, developed its own software package called FireProc.
This software package provides a means of maintaining the entire chain
of the necessary FFMS operations - from reception of information to the
generation of output products. The system includes two basic modules:
FireProcServer, and FireProcClient, as well as a variety of processing
CARBON BUDGET OF
THE BOREAL FORESTS
M. J. Apps
Northern forest ecosystems
contain a large fraction of the global stocks of terrestrial organic carbon
(IPCC 2001) and are intimately involved in the changing greenhouse gas
balance of the atmosphere (Schimel et al 2001). Significant advances have
been made in the understanding and quantification of the role of the circumpolar
boreal forest and their management to the global carbon budget; the IBFRA
conference in May 2000 was devoted to assessing this role [Apps et al.,
2002, Stocks et al., 2002, Karjalainen et al., 2002, Shaw et al., 2002].
The science has advanced considerably since the 1993 review by Apps et
al. and an update to that work is presently in press [Goodale et al.,
2002]. Of particular note is the increased awareness that these systems
are not in steady state or equilibrium and probably have never been [Apps,
1998]. Part of the explanation for the current disequilibrium is now recognized
to be the influence of changing disturbance regimes associated with direct
human activities (e.g., land-use change and land-use practices), natural
variability (e.g., in weather patterns) and the indirect impacts of human
activities (e.g., climate change).
RESEARCH IN SMALL-LEAF FORESTS
I. B. Archegova, S.
V. Degteva, F. M. Khabibullina, E. G. Kuznetsova, G. G. Romanov
in the coniferous (spruce) forests of taiga zone damaged by cutting develops
via substitution of conifers for small-leaved species, which is determined
by abrupt change in conditions (light, moisture) at the clearing areas
and by different life strategy of tree species. The results of combined
(biota - soil) complex research in secondary small-leaved (birch, aspen
and gray alder) stands are considered. Development of fast-growing deciduous
species is accompanied by restructuring of biota and biological turnover.
Considerable re-structuring of plant community is accompanied by increasing
species diversity of vascular plants and microfungi. After changing composition
of plant community, typical Podzolic soil transforms into low-Podzolic,
i.e. into new soil sub-type.
QUANTIFYING THE KYOTO
PROTOCOL: THE ESA KYOTO
O. Arino1, E. Volden1,
D. Fernandez1, S. Plummer2
The Kyoto Protocol to the United Nations Framework Convention on Climate Change (UNFCCC) commits its Parties to limit net emissions of six major greenhouse gases. For CO2 the Protocol allows offsetting gas emission reduction by sequestration of carbon in carbon stocks. Furthermore, the Protocol defines certain Cooperative Implementation Mechanisms such as the Joint Implementation Mechanism and the Clean Development Mechanism (CDM), whereby countries can also implement carbon sequestration projects in another country. However, it requires reporting of changes in the carbon stock based on appropriate measurements and estimations. This results in a growing need for services providing land-cover mapping, forest monitoring and estimations of sequestrated carbon mass in order to plan, implement, assess and get these projects. ESA aims to develop a service under the Data User Programme tailored to the exploitation of Earth Observation data for quantifying the Kyoto Protocol. The objective of this project is to define and implement a nation-wide service for reporting for, or in trading resulting from, the Kyoto Protocol. It will examine provision of quantitative estimates of changes in the carbon stock as well as monitoring with respect to afforestation, reforestation and deforestation (ARD) activities, or more generally land-use change activities.
A LAND COVER DATABASE FOR FOREST AND LAND MANAGEMENT IN NORTHERN EURASIA
S. A. Bartalev1, A.
S. Belward1, D. V. Ershov2, A. S. Isaev2
The European Commission' Joint Research Center and Russian Academy of Sciences Center for Forest Ecology and Productivity have established a land cover data base to support forest and land management throughout Northern Eurasia. This new database has been created from 1 km resolution SPOT4 VEGETATION data from 1999 and includes an update to take into account all vegetation fires (forest and other land cover types) occurring in the year 2000. The database is made up of a series of advanced products derived from the VEGETATION data, including seasonal mosaics, snow duration, directional properties describing anisotropy, wetness index, phonological descriptors and a land cover map. The map legend contains 26 classes identified so as to meet the needs of science programmes, policy makers, environmental conventions, non-governmental organisations, development-aid projects and the national forest service. The first validation step compares the percentage forest cover from the map for each administrative region of the Russian Federation with the official forest cover statistics giving an R2 of 0.93. Whilst not statistically valid for all classes this gives us confidence in the map's quality. Full statistical validation is underway with the collaboration of Russian experts. This paper describes the map legend; the advanced products used for classification; map accuracy assessment process and presents the land cover map.
EFFECT OF CLEAR CUTTING ON LITTLE RIVER DISCHARGE
I. A. Bekh, D. A. Savchuk
The effect of local clear cutting was studied on discharge of the little rivers Bolshaya Utka and Malaya Utka (left tributaries of the Ket river of the Ob river basin) in the middle subzone of taiga in West Siberia. The cutting was started in 1966 and continued for 20 years. From 1966 to 1985 the total felled area was 31240 hectares (that was 36% of forest plane of the basin) including 6920 hectares in 1966-1970, 12270 hectares in 1971-1975, 7820 hectares in 1976-1980 and 4280 hectares in 1981-1985. Annual river discharge and discharge volume abrupt increased in 5-7 years after the clear cutting, became maximum in 1975 and then reduced little by little when the forests were regenerated. Stabilization of the river discharge and discharge volume was observed in 1991-1993 that was 6-8 years after the cutting had been finished. The mean and maximum discharge volume increased in 1981-1985. From 1966-1970 to 1976-1980 the river discharge increased from 68.5% up to 73.7% during the high water. The mean duration of the high water decreased from 98 to 94 days.
LAG OF THE MULTY-YEAR TREND OF AEROSOL IN RESPECT TO THE SOLAR ACTIVITY AS A RESULT OF VEGETATION RESPONSE
B. D. Belan, G. G. Matvienko,
M. V. Panchenko
of the aerosol number density that has been carried out at the Institute
for Atmospheric Optics since 1983 revealed an 11-year cyclicity in its
variations. It is well known that such a cyclicity is typical of the solar
activity. Comparison of the long-term behaviour of the aerosol number
concentration with time behaviour of Wolf numbers showed that they were
similar. However, long-term behaviour of the aerosol concentration has
a 2(3)-year phase lag in respect to that of Wolf numbers.
VARIATION OF THE
AEROSOL CHEMICAL COMPOSITION
B. D. Belan, D. V. Simonenkov,
G. N. Tolmachev
Institute for Atmospheric
Optics has been carrying out regular (1 flight per month) airborne sounding
over southern regions of West Siberia since June 1997. Airborne surveys
are performed over forest zone in the 500 to 7000 m atmospheric layer.
In our studies aerosol is sampled onto Petryanov filters (AFA-type), which
is then analysed in the Laboratory of Analytic Chemistry of Tomsk State
OF FOREST FIRES IN TOMSK REGION
V. V. Belov, S .V. Afonin,
G .G. Matvienko
Among the tasks of remote
sensing of the Earth's surface from space there is a very important problem
of early detection and monitoring of forest fires. This problem is very
urgent for boreal forests of Russia, since more than 1250 forest fires
were detected only in the Tomsk Region (Western Siberia) in 1998-2001.
Since 1998, the Institute of Atmospheric Optics SB RAS has operated the
system for real-time space monitoring of forest fires (SMFF) on the territory
of Tomsk Region with the use of AVHRR/NOAA data. The efficiency of this
system in 1998-2001 is analyzed thoroughly in this report. Such an important
problem as the efficiency of early (as compared with the results of forest
protection services) detection of forest fires from space is considered.
It is shown how the SMFF efficiency depends on the fire area and the time
of space monitoring. The problem of rejection of sun glints on space images,
which is urgent for Tomsk Region, is discussed.
INFLUENCE OF HIGH
ALTITUDE ON NEEDLE STRUCTURE
O. G. Bender, N. A.
Vorobjeva, S. V. Zagirova
and ultrastructural organization of one-year-old needles of 10 - 15-year-old
Siberian stone pine seedling growing at 2100 m and 1710 m altitude in
Seminsky Pass, Mountain Altai was researched. It is shown, that the extreme
conditions of high mountains altitude influence morphology and anatomy.
The changes influence mesophyll, resin canals, epidermis. At high altitude
needle length decreases, its thickness increases, mesophyll, vascular
bundle and resin canal portion of the leaf cross-sectional area decrease
and the epidermal thickness increases.
OF ABOVEGROUND AND UNDERGROUND PHYTOMASS
A. V. Ben'kov, S. V.
Tokmakov, V. Y. Kaplunov
The Gmelin larch (Larix
gmelinii Rupr.) is main wood species of Eastern Siberia boreal forests,
forming monodominant stands on permafrost soils. Under these specific
conditions the forest ecosystems are characterized by the specific forest
recovery process, low productivity and attenuated reduction potential.
However, the larch forests on permafrost soils are stable ecosystems.
With the aboveground phytomass structure the resistivity of trees to extremal
environmental factors is determined by development of their rootlets.
The root stores are well investigated for average latitudes, however they
are scantily explored for North regions. The investigation was made on
stationary research plots of Turuhanski research station (r. Niznaja Tunguska
inferior streaming, western border of Evenkia). The relations of stem
and root mass were studied in postfire overmature 380-year-old and mature
110-year-old larch forests.
INFLUENCE ON GROWTH OF DOMINANT
A. V. Benkova
Growth rate of the woody
plants in stands depends on both physiological properties of the species
and environmental conditions. Weather conditions of growth season do determine
annual variability of biomass increment. In this work the difference in
response of radial increment of dominant and suppressed fir trees (Abies
sibirica Ledeb.) to weather changes has been revealed. The material of
this study consists of 19 sample trees of fir (Abies sibirica) growing
in the stand in boreal forest zone of Central Siberia near Vorogovo (61░
01? N 89░ 46? E). The trees were divided into three groups by diameters:
(1-10 cm), (11-20 cm) Ŕ (21-32 cm). The period from 1936 to1989 has been
OF WOOD ANATOMY IN THE SIBERIAN
V. E. Benkova, A. A.
Among many mechanisms,
which determine stability of northern forest ecosystems, superdominance
of larch species is of the most importance. Larix gmelinii (Rupr.) Rupr.
and L. ˝ajanderi Mayr form mono-specific larch forests in a wide territory
of cryolithic zone, including northern timberline. It is obvious that,
during the evolution, these species have made a number of environmental
and biological hereditable features which provide their dominant role
in permafrost conditions and other extreme environments [Abaimov et al.,
2000]. They are manifested in a wide range of adaptive mechanisms, reflected,
in particular, in structure of secondary xylem.
THE CHANGES OF NUTRIENT
STATUS OF SCOTS PINE FOREST
N. S. Berezhnaya
Element composition in the Scots pine (Pinus sylvestris L.) needle of trees suppressed by emissions was studied. Significant disturbances of nitrogen, phosphorus, potassium, calcium, magnesium, sodium, zinc and manganese were observed. Essential increase of the concentrations of nitrogen, calcium, sodium and the decrease of phosphorus, potassium, manganese and zinc were found in the needle of the heavily and moderately weakened tree stands. The following pollutants: fluorine, sulphur, aluminium, silicon, lead, cadmium, mercury, iron, copper showed accumulation levels that were clearly above the natural background levels. Low weakened trees showed minor changes of nutrients status compared with the background trees. Accordingly, accumulation of the pollutants in the needle of these trees was insignificant.
A REVIEW OF ADVANCES
IN INTERNATIONAL REMOTE SENSING PROGRAMS AND RESEARCH METHODS USED TO
STUDY FOREST DYNAMICS
K. M. Bergen1, S. A.
Bartalev2, V. Ippolitov3
Russia's great geographic extent and the continual dynamics of its forests are the reasons remotely sensed data is used in studying forest and carbon dynamics over its territory. Remote sensing data is the most efficient means of assessing large forest areas, and multi-spectral and repeat imaging allows for effective scientific monitoring of forest dynamics. Beginning in the 1960's, a growing number of sensors have collected data useful for assessing the Russian boreal forest, the most significant including the Russian platforms Resurs-O and Resurs-F; U.S. platforms or sensors AVHRR, MODIS, Landsat and Corona; and other international platforms including SPOT (France), IRS (India), ERS (Europe), Radarsat (Canada) and JERS (Japan). In the ten years since the formation of the Russian Federation, international collaborations between both agencies and individual scientists have been growing. This paper documents the changing nature of remote sensing data access and organization for the various platforms and sensors; and reviews research results related to carbon, including land-cover change, fire, logging, and insect/pollution damage. It first reviews Russian, U.S. and European and other remote sensing platforms, data organization and research results, and concludes with sensor fusion: bringing international data and remote sensing programs together.
FOREST RESOURCES OF THE MAGADAN REGION
A. N. Berkutenko1, V.
I. Chunaev2, A. N. Polezhaev1
Magadan region is located
in north-eastern part of the Russian Federation. Its area including adjacent
islands is 46240.000 ha. On 01.01.2001 44694.000 ha or 96.7% of the whole
area belongs to state forest fund. Severe climatic conditions, permafrost,
short vegetation season, poor peat soils create unfavorable conditions
for forest vegetation. This can explain not big diversity of trees and
shrubs. Forest coverage in Magadan region makes up 33.6%, it varies in
different administrative districts from 23% in North-Evensk district to
65% in Srednekansk district. The main forest forming trees occupy 41.2%,
shrubs - 58.8%. Larch occupies 96.7 % of the area, poplar - 2.2%, chosenia
- 1%, birch 0,1%, shrubby birches - 21.6%, other species of shrubs - 3%.
SCALING UP NPP ESTIMATES
FROM THE SITE
P. Y. Bernier1, F. Raulier1,
The measurement of net primary productivity (NPP) and of its component processes is performed at the level of a plot. Yet, spatial applications to the question of climatic influences on carbon sequestration in forests requires that NPP predictions be scaled up from the plot to large landscapes up to the full extent of Canada's boreal forest. A scaling up exercise of NPP from plot estimates to the Canadian landscape was performed in two steps. In the first step, a validated process-based model of canopy gas exchange (FineLEAP) was used to develop parameter values for a stand-level spatial model of NPP (StandLEAP). In a second step, StandLEAP was run on a 30x30m spatial resolution for 10 regions of 1000km2 to 2000km2 in size distributed across Canada. Results from these simulations were used to obtain parameter values for a simpler model (ForLEAP) to be applied on pixels of 1km2 or larger. This multi-scale approach permits the proper integration of field results into spatial models, as well as validation of estimates at the proper spatial scale.
TRANSFORMATION PROCESSES IN BOREAL FOREST LITTER
P. Bienkovski, A. A.
Titlyanova, S. V. Shibareva
The litters of coniferous
forests were analyzed along the latitude gradient (60-68?N) in the series:
south taiga, north taiga, forest-tundra. The elementary composition and
the hearing value of litters change along the gradient. In ash-free organic
matter the Đ content averaging from 48.5 to 54.0% is independent of the
forest type and landscape zone. The N concentration varies from 0.61 to
1.53% and increases northward. The 0 content increases (from 32 to 41%)
and H content decreases (from 6.9 to 6.5%) along the gradient also northward.
TIMBER INDUSTRY COMPLEX
IN SIBERIA - STRATEGIES OF SURVIVAL
Y. Sh. Blam, L. V. Mashkina,
O. V. Mashkina
Timber industry is highly
effective only when it includes a complex raw material treatment. It is
considered that with a raising export duties for round timber, it is possible
to stimulate the sector of in-depth timber treatment; in this case the
bankruptcy of smaller woodsmen would be unavoidable. Experts also consider
the need for creation of the single federal structure, dealing with the
timber industry issues, which by itself without a thought through forest
policy would not be able to increase the effectiveness of the timber complex.
Often the higher effectiveness in timber export is achieved through the
CHANGE OF VEGETATION
IN RUSSIAN FAR EAST DURING THE NEOGENE
N. I. Blokhina
Change of vegetation
in Russian Far East (RFE) during the Neogene was closely associated with
global climatic changes. After climatic pessimum at the Paleogene-Neogene
boundary a gradual warming trend began. In the climatic optimum during
the late Early Miocene mesophytic types of rich polydominant both broad-leaved
hardwood and conifer-hardwood forests grew over the RFE. These deciduous
forests included a high percentage of thermophylious plants and several
SOIL WATER EVAPORATION
P. P. Bobrov1, T. A.
Beljaeva2, A. P. Bobrov2
In this paper, the experimental results obtained from the studies of soil water evaporation with the use of microwave radiometers are presented. Through mathematical modeling, it has been shown that there is quite a strong correlation between the rate of evaporation and soil moisture content dynamic in the upper layer of 6 cm in depth. The microwave radiometry at wavelengths from 18 to 30 cm was proposed as an effective approach to remote measuring of the total water content in the soil layer. In the experiment conducted, the radiometer at 18 cm wavelength was applied for estimating water content inside the layer of 1.5 m in depth. The highest level of correlation between the rate of evaporation and value of microwave emisivity is observed during the evening hours when the soil moisture gradients with depth are usually minimal. Some aspects of the radiometric methods, which can be used for monitoring the dynamic of water content in soil, are discussed in terms of their accuracy and domain of applicability.
OF PRIORITY RESEARCH TARGETS
V. N. Bocharnikov1,
T. V. Chernenkova2
This year the World
Summit on Sustainable Development (Johannesburg, September 2002) is a
candid assessment of the progress that has been made in implementation
of global plan for sustainable development that was agreed at the Rio
Earth Summit in 1992. The green belt of Russian boreal forest along Russian
North, Siberia and Far East, and less Scandinavia and Canada may be regarded
as one of the most important world areas supporting indigenous peoples
with their traditional livelihood some last several centuries. Within
this framework we would like to highlight some important elements for
a programme of development on inventory ideology and monitoring methods
of forest biological diversity.
EMPIRICAL MODEL OF
BIOGENIC COMPONENT OF ATMOSPHERIC
A. I. Borodulin1, A.
S. Safatov1, B. D. Belan2, M. V. Panchenko2
From 1998 up to now State Scientific Center of Virology and Biotechnology "Vector" and Institute of Atmospheric Optic carry out systematic study of the biogenic component of atmospheric aerosol at different altitudes in the south of West Siberia. Atmospheric samples are collected from onboard the AN-30 "Optic-E" aircraft-laboratory. The flight path is situated over the Karakan forest located on the right coast of the river Ob'. Sampling is carried out at the heights of 7000, 5500, 4000, 3000, 2000, 1500, 1000 and 500 m under clear weather conditions in the daytime. Air samples for determination of atmospheric protein concentration are collected on the AFA-HA filters, and samples for determination of concentration of microorganisms are collected to impingers. The volume of air sampled at each altitude is about 2 m3. Impingers are filled with special liquid based on physiological solution, and the volume rate of sampling is 50l/min at the flight duration at each altitude of 15 min. The data of observations show that the concentrations of protein molecules and living microorganisms have their own well pronounced annual behavior.
STABILITY OF BOREAL FOREST ECOSYSTEMS IN CONNECTION WITH GROWTH TYPES DIVERSITY AND STRUCTURE OF TREE STANDS
A. I. Bouzikin, I. S.
Dashkovskaya, V. G. Soukhovolsky
The problem of forest
stand stability is one of fundamental problems of forest ecology. The
stability of boreal coniferous forest ecosystem can be connected with
different vital strategy types. The stability of forest stands can be
supported through various reaction types on external influence and various
growth strategies of one-breed trees. Five basic growth strategy types
were discharged. It is shown that in a steady stand there are definite
interrelations between the number of trees with different types of strategy.
For the analysis of stand stability factors the parameters describing
a degree of synchronisation of a radial increment of all trees in a forest
stand in separate concrete year are entered. The connection of a level
of tree growth synchronisation and the weather factors is investigated.
It is shown that the degree of tree increment synchronisation in forest
stand can change in dependence of climatic parameters.
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