CARTOGRAPHIC ESTIMATION OF TREE PARAMETER DYNAMICS IN RUSSIAN NORTHWEST

The article presents an analysis of spatial variability and temporal dynamics of tree plant condition indicators in the regions of the Russian Northwest over 2008 – 2010 based on the regular network of ground monitoring organised under the ICP Forests international programme. Indicators for trees of dominant species in permanent observation plot (POP) included defoliation, discoloration, condition category, and damage extent. The indicator dynamics was assessed based on procedures of geo-informational mapping and spatial analysis taking into account landscapefocused POP and human-induced impact. The total of 710 POP were analysed in six regions of Russia: Leningrad Region, Pskov Region, Novgorod Region, Kaliningrad Region, Murmansk Region, and the Republic of Karelia. As the research showed, indicators like defoliation degree and share of damaged trees were the most informative (sensitive to primary types of impact). Tree plants with a high level of defoliation were found in softwood forests formed in glaciolacustrine landscapes of low platform plains and in landscapes of high platform plains (Precambrian shields and ridges with glacier expressions) in the Republic of Karelia and Leningrad Region (Karelian Isthmus). The share of damaged trees increased from 23% in 2008 to 39% in 2010. Maximum values of the indicator (above 80%) over the entire observation period were found in four regions: the Republic of Karelia (predominantly on the Karelian Isthmus), Leningrad Region, Murmansk Region, and Kaliningrad Region. Occurrence of the most dangerous biotic causes of tree damages was high in Leningrad Region and the Republic of Karelia. The share of trees with diseases was higher in north taiga forests (30%) as compared to middle taiga forests (24%) and south taiga forests (19%). To the highest extent, the damage was manifested in POP focused on sand landscapes and in Precambrian shields and ridges of high platform plains. In general, the cartographic analysis of monitoring data collected over 2008-2010 showed the Karelian Isthmus (Leningrad Region) where middle taiga forests were steadily characterised by the worst average condition of tree plants within the entire ICP Forests network.

network based on geographic coordinates with the cell size of 32х32 km was developed, and networks of 16х16 km were developed in other regions. Some scientists believe that the established regular network can potentially be used as a framework and scientific infrastructure for integrated studies of biodiversity among regions as well as for national inventory of forests (Alekseev et al., 2007, Bakhmet et al., 2011, Knyazeva et al., 2013. Ground monitoring is arranged at two levels. The first level includes assessment of tree crowns, condition of soils, nutritional condition of tree plants, and biodiversity of plants. Condition of tree species is estimated based on indicators like crown defoliation degree, discoloration degree, tree condition category, damage and causes of damage (insect pests, diseases, etc.) as well as composition of photosynthesising organs in tree plants. The soils are characterised based on their morphological description, physical composition, acidity level, and chemical content. Assessment of plant biodiversity is based on details and structure of species. First-level ICP Forests monitoring in Russia is organised with 710 POP. Observation frequency suggests annual measurement of crown defoliation, discoloration, condition category, and damage of trees; measurement of plant biodiversity indicators once in five years; assessment of soil and nutritional condition of trees once in 10 years. The second level monitoring additionally includes collection and analysis of atmospheric precipitation samples and ground waters where the level of acidity and concentration of chemicals is measured.
Since 2006, the ICP Forests national coordination center in Russia has been the Center for Forest Ecology and Productivity of the RAS (CEPL RAS). The center organised a database maintained by the database management system MySQL that provides multi-user access to ICP Forests monitoring data. To represent monitoring data in a cartographic form, the professional ArcGIS software is used.
This study was aimed at representing the sprucest results of tree condition analysis based on maps of parameters developed through the ICP Forests monitoring of over three years (2008 -2010).
Cartographic methods allowed assessing spatial trends of change in condition of tree plants and identifying the causes and effects between monitoring indicators and landscape characteristics as well as the sources of human-induced impact. This paper was based on the CEPL RAS reports in Most part of the Republic of Karelia is occupied by ridge-and-hill lake plains whose altitudes are decreased from west to east. Morainic undulating and lake-and-glacier sand plains are widely spread in the terrain, with frequently occurring outcrops of crystalline rocks. The southern part of the region is characterised by alternation of undulating swampy plains with ridges and hills.
The boundary between the north and middle taiga forests goes approximately at the level of Lake Segozero. The north taiga is dominated by pinewoods, while the middle taiga is dominated by pinewoods with spruce woods. Sphagnum pinewoods primarily grow in poor soils of swampy plains and swamps, while moss pinewoods grow in higher parts of the plains. Moss spruce woods (sometimes with birches and aspens) predominate among spruce woods, which grow on the richest soils.
The area of Leningrad Region is mostly plain with insignificant absolute elevations. The area of the Karelian Isthmus is a part of the Baltic crystalline shield marked by broken ground, multiple rock outcrops and large number of lakes. Lowlands are primarily located on the banks on the Gulf of Finland and Lake Ladoga as well as in the dales of large rivers. Vegetation of landscapes is represented by boreal south taiga forests, with middle taiga forests located in the north-eastern part of the region. Transition from coniferous forests to mixed forests is found in the south. Forests occupy about a half of the region's area. This area is peculiar for having been developed by humans for a long time, which resulted in strong depletion of forest resources.
Indigenous pine and especially spruce woods partially remained in the north-western and eastern parts of the region, but are primarily replaced by derived small-leaved forests and underwood  (birch, aspen, grey alder). A significant place in the vegetation cover of the area is occupied by swamps, predominantly of raised type.
The area of Novgorod Region represents a low flat lake-and-glacier and ancient alluvial plain with small areas of hilly and morainic terrain. Primary forms of terrain are vast outwash swampy plains. By its landscape, Novgorod Region is divided into plain western part and high eastern part. In the north of Novgorod Region, south taiga trees grow while sub-taiga coniferous and wide-leaved (mixed) forests predominate in the central and southern parts of it. Birch and pine predominate in the mixed forests of the south taiga. Significant species of coniferous and wideleaved (mixed) forests are mainly represented by secondary aspen and birch forests with wideleaved species like linden, maple, and oak.   The north-eastern part of the region is occupied by a glaciolacustrine plain where individual hills are found. A hilly and morainic ridge is attached to the plain from the west with a large arch across the entire region. The north-eastern part of the region has a lake-and-glacier lowland whose individual areas are below the Baltic Sea level, which also causes swamping. The region's vegetation cover belongs to boreal sub-taiga landscapes and represented by coniferous and wideleaved (mixed) forests. Primary forest forming species are spruce, pine, oak, male, and birch.
Spruce is common in forest areas of eastern parts of the region and occupies 25% of the forest area.
Pine forests occupy about 17% of the forest area in the region. Oak forests are represented by individual small areas with European oaks, aspen and linden forests also encountered. There are small areas of beech forests. Up to one-fourth of the forest areas are occupied by birch forests. Low areas of soils with long-term excessive moisturizing are occupied by black alder.

SAMPLES AND PROCEDURES
Ground studies of tree plants were conducted visually and instrumentally using a standard methodology of ICP Forests on the regular monitoring network. Network nodes have POP representing clusters of four accounting points equally distanced from the POP center in any direction. At least six trees of a dominant species were selected in each subplots (24 trees per POP) along with trees of other species located closer than the sixth tree to the middle of the subplot. Thus, up to 50 examined trees could be in a single POP (Methodological guidelines…, 2009). Table 2 represents the number of POP by regions (with numbers of examined trees indicated in brackets) where observations were made over the three years. Since new POP were established every year during initial monitoring (and not all existing POP were covered by annular observations), their number changed respectively. In order to obtain the dynamics of tree species indicators on the monitoring network, an attributive database was created in MySQL to assess crown condition and damage of tree plants.
MySQL represents a high-performance multi-user DBMS built using client/server architecture and provides an opportunity to divide resources and provide access to the database server over a network. To organise MySQL operation, a server was used, which allows working with data both from a local network and via Internet.
Tables for condition of forests and forest formation factors have been developed in accordance with the data structure. The relational data model used to build the information system database technically represents a set of tables interrelated by key fields . A single table corresponds to any specific class of objects (POP, model trees, tree species) or parameter (list of protection categories, age of damage). The database includes fifteen guides and eleven operational tables. The database is based on three operational tables: POP description, model trees and crown condition.
The first table is filled in with all parameters belonging to POP and forest organization allotment where this plots is installed, while two others are filled in with constant tree characteristics (species, number) and annually defined parameters (Eydlina, Knyazeva, 2014).

First level monitoring indicators suggesting annular observation of model trees in POP
include two groups: assessment of crown condition and description of indications and damage.
Assessment of crown condition includes parameters of defoliation, discoloration and category of sanitary condition.
Defoliation means premature fall of leaves or spruce needles due to unfavourable environmental factors. Defoliation is estimated as percentage relative to the fully leaved tree. The following classes are distinguished with the range of 5% (0-5, 5.1-10%, etc.).
Discoloration means change in colour of leaves or spruce needles due to human-induced or natural impact. Discoloration level is ranged from 0% to 100% with the range of 5%.

STUDY RESULTS AND DISCUSSION
The temporal dynamics of condition of tree plants by regions and that of spatial interrelations with landscape conditions of forest vegetation and human-induced impact was identified by analysing a series of asynchronous maps of parameters and maps of dynamics.
A high degree of crown defoliation was noted in pine trees forming north taiga forests on accumulative marine and sand landscapes of low platform plains (17%), middle taiga forests on Precambrian shields and ridges of high platform plains (15%) and south taiga forests on glaciolacustrine sand and morainic landscapes of low platform plains (15% each). For spruce and birch, a high degree of defoliation (16% and 15%, respectively) must be noted in middle taiga forests on morainic landscapes of low platform plains and in south taiga forests on karst plateau on limestones, dolomites and gypsum of high platform plains (16% and 21%, respectively).
The dynamics analysis of average estimates of defoliation of dominant tree species in POP shown that discoloration average is below 5%. Most frequent values of discoloration were 0-5 % and 5-10 %. Spruce and pine discoloration degree was significantly lower than defoliation and averagely reaches 7-9%. An increased degree of discoloration of pines of sub-taiga forests on glaciolacustrine clays and loamy landscapes of low platform plains must be noted: to 16% in 2009, and to 25% in 2010, respectively. The birch discoloration degree reached 13% in north taiga and middle taiga forests that grow on crystalline plains as well as in middle taiga forests that grow on undulating morainic and kame soils of high platform plains.
Distribution of trees of major forest-forming species by categories of condition in the entire network showed that the share of healthy trees in the monitoring network varied from 75% to 80%, the share of weak trees is 14 to 20%, and the share of extremely weak trees is 3 to 6% ( for pine, 11% to 31% for spruce and 17% to 30% for birch. Primary causes of damage were fungous diseases, insects as well as abiotic factors.
Let us consider the detailed change in condition of dominant tree species in POP in the monitoring system for each region.

Murmansk Region
No examinations of tree condition were conducted in 2008. In 2009-2010, an examination using the ICP Forests international methodology was conducted in 35 POP. In 2009, most POP (60%) showed the average defoliation of crowns of dominant tree species below 5% (Fig. 3B).
Maximum values reached 23-27% on two POP only. In 2010, the number of POP with trees whose defoliation degree exceeded 5% was half of the total number of POP, and defoliation values also increased a little, averagely by 2-5% (Fig. 3C). However, the maximum values of defoliation

Republic of Karelia
The totals of 129 POP were examined in 2008. Most POP showed the average defoliation of dominant trees below 15%. However, there were groups of POP in the north of Karelia and in the middle to western part (Muyezerskoye and Suyarovskoye forest districts) with rather high defoliation of 21% to 45% (Fig. 3A). Dominant species of pines aged 120-180 grow in those POP.
Landscapes are represented by low and high platform plains (Precambrian shields and ridges with glacier expressions). The share of POP where blister rust was found in trees was 12% in 2008, 19% in 2009, and 20% in 2010. Most POP of the kind was located in the central eastern part of the region in the Belomorskoye and Segezhskoe forest districts.

Leningrad Region
Examinations of 155 POP located in the eastern and north-western parts of the region were carried out in 2008. The central and south-western part of the region was almost not examined, except for some single POP. Average defoliation of tree crowns of dominant tree species was rather highit exceeds 15% for most POP. Maximum defoliation (above 25%) was found in POP located in the north-western part of the region on the Karelian Isthmus and in the farthest south-eastern part Maximum defoliation was found on the Karelian Isthmus as in 2008: 20% to 45%. High defoliation of tree stratum was found in POP in the central part of the region: 15-35% (Fig. 3B, 3C). Average discoloration in 2009 and 2010 for most POP was within 0% to 10% but the number of POP with crown discoloration above 10% almost doubled (Fig. 5B). Highest discoloration of tree stratum crowns (15-23%) was found in the same POP that had high defoliation. Tree decreased by 10-20% (Fig. 4A). The average defoliation level decreased in 2009-2010 in the POP located along the Finnish border but remained the same in the other parts of the isthmus (Fig. 4B).
In general, a significant reduction of defoliation was recorded in 2008-2010, averagely by 15% (Fig. 4C). Nevertheless, defoliation of tree plants in POP of the Karelian Isthmus remained one of the highest in Leningrad Region.
About half of the trees in POP in Leningrad Region in 2008 remain in weak condition (Fig.   6A). Most POP showed the share of damaged trees of dominant species below 40%. Only two POP showed more than 80% of damaged trees (Fig. 7A). Primarily, weak trees belonged to coniferous species of ripe and ripening age. Most POP with the weak category of condition were concentrated on the Karelian Isthmus.
The sanitary condition of tree stratum aggravated in 2009. The trees were qualified as healthy in one POP only and found extremely weak in four POP. More than half of damaged trees were found in 38% of the POP. The Karelian Isthmus showed aggravation: all POP had damaged trees, with their share exceeding 50% in half of them. Most damage was recorded in POP located in the western part of the region (Fig. 7B). Quite a high number of POP with weak trees was found in the central part of the region in the Kirishi, Kirovsky and Lyubansky forest districts. The weakest trees were represented by coniferous species aged 65-120 years and older.
Minor positive dynamics was observed in 2010 for the category of sanitary condition in POP of the Karelian Isthmus: trees were acknowledged healthy in 14 POP, and only two POP had weak trees (Fig. 6B). The maps of parameters clearly showed that multidirectional process by years, but, in general, moderate positive dynamics was found in 2008 to 2010 in the condition of tree stratum on the Karelian Isthmus (Fig. 6C). The dynamics of healthy/damaged tree ratio in POP was gradually becoming negative. In 2010, 80% of POP on the Karelian Isthmus had more than 50% of damaged trees (Fig. 7). Due to most dangerous causes of tree damage for 2008-2010, blister rust was found in the north-western part of the region (primarily damaging the coniferous trees). No dangerous causes of damage were found in most POP.

Novgorod Region
Ground 15%. Only in two POP located in the Opochenskoye forest district, the defoliation rate was 21% (Fig. 3A). Average crown discoloration exceeding 10% was recorded in four POP of the region (Fig. 5A). Average defoliation in 2009 was below 15% (Fig. 3B). The situation aggravated for discoloration: in 12 POP, crown discoloration of dominant species exceeded 10%, being 30-35% in two POP. High defoliation of 11-30% was noted for those POP. The POPs are primarily located in the Pechorskoye and Porkhovskoye forest district in the central part of the region. Average defoliation in POP in 2010 was significantly below 10%, crown discoloration in all POP was low (below 8%). Maximum defoliation was found in the northern part of the region (Fig. 3C, 5C). It should be noted that POP where high defoliation was recorded were examined for 2008 to 2010 only once and therefore there has been no dynamics analysis. Primary changes of defoliation indicator on 25 POP took place in 2009: defoliation decreased by 10-20% in the south-eastern part of the region while the defoliation of tree crowns increased by 5-10% in the north-western part of the region (Fig. 3C). Defoliation fluctuated in 2009-2010 within 5%; in other words, it remained almost unchanged (Fig. 4C). The discoloration dynamics was insignificant, since average values by years changed within 0-10% (Fig. 5C).
Only 4% of POP in 2008-2009 had trees with a weak category of condition (Fig. 6A). All Gradual minor aggravation of crown condition expressed by discoloration indicators can be noted for POP of Kaliningrad Region. In 2008, there was almost no crown discoloration of dominant tree species in POP, and only three POP had verge discoloration within 1-5% (Fig. 5A).
The negative change in discoloration was well noted on the maps of parameters for discoloration ( Fig 5C). The sanitary condition of trees in POP remained stable for the entire period of observations: only two POP showed weak trees (Fig. 6).
In 2008 northern and western parts of the region (Fig. 7A). In 2009, the number of POP with damaged trees above 50% reduced to 18%, and remained at 9% in 2010 (Fig. 7B). By 2010, the situation in the Slavskoye forest district improved significantly in the northern part of the region: no more than 20% damage of trees of dominant species was found in POP (Fig. 7C). Only POP No. 8 (where maximum values of defoliation and discoloration were found), showed more than 80% of damaged trees. Most dangerous causes of damage in the region included only blister rust (in 2-3 POP). In general, we can conclude of a gradual decrease in total number of damaged trees and of POP with the highest degree of damaged trees.  In general, the cartographic analysis of dynamics of tree species condition over 2008-2010

CONCLUSION
shows Leningrad Region (especially the Karelian Isthmus) where middle taiga forests were steadily characterised by the worst average condition of tree plants within the entire ICP Forests network.
This can be related to a combined impact of natural (landscape type, biotic damage) and humaninduced factors, in particular, recreational loads and effects of air contaminants. A large number of sick and damaged trees can also be found in near-tundra and north taiga forests in Murmansk Region and the Republic of Karelia. To the highest extent, the damage was manifested in the POP focused on sand glaciolacustrine landscapes and shields and ridges with glacier exposure of high plains. However, in order to find reasons and identify the condition of tree stratum accurately, we need to increase density of the observation network since the current cell size of 32 x 32 km (with annual observations undertaken on the 64 x 64 km network) is insufficient. Indicators like defoliation degree and share of damaged trees were the most informative (sensitive to primary types of impact). Discoloration and condition categories were less variable, which may be related to the higher bias in estimates during fieldwork and features of calculation methodology for average values.