Influence of climate on Scots pine growth on dry and wet soils near Lake Engure in Latvia/Kliima moju hariliku manni kasvule kuival ja marjal pinnasel Engure jarve aares Latis.
The distribution of trees is generally determined by their ecological characteristics. Both internal and external factors, e.g. climate, influence the growth of trees. Many dendroclimatological studies have shown that climate explains a relatively large part of the temporal variability in tree-ring width (Fritts, 2001). The relationship between climate and tree-ring width occurs because plant growth is affected by specific conditions in the habitat environment. In addition, the nature of soil where trees grow may affect their response to climate (Linderholm, 2001; Linderholm et al., 2002; Vitas & Erlickyte, 2007; Weber et al., 2007).
Scots pine (Pinus sylvestris L.) has a very wide ecological amplitude and successfully occupies dry habitats and sandy soils as well as peatland habitats. Therefore, it has a wider geographical distribution than any other pine species (Ohlson, 1995; Richardson & Rundel, 2000).
Tree rings of Scots pine have been successfully used in dendroclimatology, mainly regarding trees growing on dry soils. Dendroclimatological investigations of tree rings in Latvia (Spalte, 1975, 1985; Skudra, 1982; Elferts, 2007a, 2007b), Lithuania (Bitvinskas, 1978; Vitas, 2004; Vitas & Erlickyte, 2007), Estonia (Laanelaid, 1982; Laanelaid & Eckstein, 2003), Poland (Cedro, 2001, 2006), and Scandinavia (Linderson, 1992; Linderholm, 2001; Linderholm et al., 2002) show that Scots pine growing on dry soil is sensitive to cold winters in the area around the Baltic Sea. Several studies treat the growth of Scots pine on peatlands. These have focused mainly on bogs and little is known about Scots pine growth on fens. Most of the previous studies examine relationships of pine growth on drained fens from a wood production improvement perspective (Pyateckij, 1963; Zalitis, 1967, 1968). There are only a few studies where the age and size of Scots pine as well as some habitat factors (nutrient characteristics of the peatlands and climate) are examined in relation to the natural regeneration of this tree species on fens (Agren et al., 1983; Ohlson, 1995).
In pristine peatlands, e.g. fens, the most important differences in comparison to mineral soil sites are a high water table level (Boggie, 1972; MacDonald & Yin, 1999), poor soil aeration, and low nutrient availability and uptake, which control seedling survival (Agren & Zackrisson, 1990; Ohlson & Zackrisson, 1992; Sarkkola et al., 2004), and extremely slow growth of trees (Ohlson, 1995; MacDonald & Yin, 1999; Fritts, 2001; Hokka & Ojansuu, 2004). Water table depth is regulated by several factors, of which temperature and precipitation are the most important in controlling seasonal and yearly variation. This means that both of these factors influence tree growth directly and indirectly through regulation of the water table by evapotranspiration (Fritts, 2001; Linderholm et al., 2002). Climatic amelioration has been of great importance with regard to the comparatively successful regeneration of pine and spruce on peatlands (Agren et al., 1983).
Ohlson (1995) observed that on fen sites the growth rate of Scots pine is greater and much more variable than on bog sites. Therefore, we suggest that Scots pine growing on fens can be more useful in dendroclimatology compared to pine growing on bogs. The aim of this study was to determine the climatic factors influencing the radial growth of Scots pine growing on dry and wet soils near Lake Engure in Latvia.
MATERIAL AND METHODS
Lake Engure is situated at the western coast of the Gulf of Riga, from which it is separated by a 1.5-2-km wide dune area. It is the largest relict lake in the coastal area of Latvia and has remained there since the time of the Litorina Sea (Viksne, 1997; Pakalne & Kalnina, 2005). It is a protected nature area, founded in 1957 as a restricted ornithological area (nowadays a nature park). Since 1989, the area has been on the European list of most significant bird habitats and, since 1995, it has been included in the Ramsar Convention on Wetlands of International Importance list (Viksne, 1997). Lake Engure is connected to the Gulf of Riga through a canal, which was built in 1842. The water level in the lake then dropped by about two metres. To the east, on the higher ridges of the exposed area, Scots pine forests developed. In lower areas an extremely rich fen community of Schoenetum ferruginei is found (Pakalne & Kalnina, 2005).
[FIGURE 1 OMITTED]
Scots pine trees were sampled from two sites (a dry soil and a wet soil site) near Lake Engure, Latvia (Fig. 1). On the dry soil cores were collected from trees growing in a Scots pine dominated forest on dry, well-drained, podzolic sandy soil, corresponding to Vacciniosa site type (Latvian typology, see Buss, 1981). On the wet soil cores were collected from trees growing at the edges of a wet depression covered by fen vegetation. The soil at the edges of the fen was organic. The pine around the edges of the fen probably invaded the site after the water level in Lake Engure dropped due to the drainage project. The forest growth conditions at the fen edge correspond to Caricosa-Phragmitosa site type (Buss, 1981) in the Latvian typology, or a tall-sedge pine fen in the Finnish peatland classification (Vasander, 1996).
Climatologic data (mean air temperature and precipitation sum; Fig. 2) were obtained from the Latvian Environment, Geology, and Meteorology Centre for the Mersrags Meteorological Station. The analysed period was 1896-2005.
In total, 32 climate parameters were used. These included 16 temperature and 16 precipitation sum parameters: mean monthly, yearly (from previous-year October till current-year September), previous-year, dormant-period (from previous-year October till current-year April), and growing-period (from current-year April till September) temperature and precipitation.
[FIGURE 2 OMITTED]
Sample collection, measurement, and chronology development
The Scots pine samples were collected in 2006. Tree-ring width samples (wood cores) were taken from the oldest trees, based on visual appearance such as tree height, stem diameter, and shoot and crown shape. Two tree-ring samples per tree were taken with an increment borer from opposite directions; in total 20 trees on the dry site and 60 trees on the wet site were sampled. If trees were tilting, samples were taken 90[degrees] from the tilting direction (Schweingruber, 1988). For the tree-ring width measurement a LINTAB 'measuring table' connected with TSAP software (Rinn, 1996) was used. Cross-dating and quality control of tree-ring measurement were performed using the program COFECHA (Holmes, 1983). After tree-ring width measurement and quality control, the mean tree-ring width was calculated for each tree. To analyse the relation between climate parameters and radial growth the long-term growth trends were removed by detrending using the ARSTAN program (Holmes, 1999). After detrending all tree-ring series from one site were summarized to one site chronology (using ARSTAN). For climatic analysis a residual chronology was used. The residual chronology was obtained by double detrending and auto-regressive modelling (Holmes, 1999).
Pearson correlation analysis was performed using SPSS (linear regression method) (Morgan et al., 2004) to determine statistically significant (at [alpha] = 0.05) relations between data. The residual chronology and all climate parameters (precipitation sums and mean temperatures) were used in the analysis.
Multiple regression analysis was performed to determine the part of chronology value variation explained by climate parameters. For multiple regression analysis SPSS was used for all chronologies. The predictors (factors) that were included in the regression equation were selected using 'response function' analysis in the program Dendroclim2002 (Biondi & Waikul, 2004).
For the dry site 18 of the 20 cored trees were measured and used for the chronology building. For the wet site the residual chronology was built from 25 trees. The length of the dry site chronology was 201 years and of the wet site chronology, 98 years (Fig. 3). Some of the samples from the dry site had very narrow and undistinguishable tree rings in the last 60 years due to declining growth. This part of the cores also easily developed cracks during coring. In these cases, the later part of the series was removed because cross-dating was impossible. This resulted in a decreasing sample depth (Fig. 3). Correlation between the two chronologies was statistically significant (0.369).
[FIGURE 3 OMITTED]
Both chronologies have a significant correlation with February, yearly, and dormant-period mean temperatures, but the chronologies have no common significant precipitation parameters (Table 1). In addition, temperatures in January, during the whole dormant period, and in the growing period at the dry site and in March and July at the wet site were significant. Response to precipitation was lower than to temperature on the dry site, being positive and significant in late winter (February), during the whole season, and the growing period. Precipitation sum prior to the growing period negatively and significantly affected the subsequent pine growth on the wet site.
On the wet site climate parameters (February temperature and precipitation sum of the previous year) explained 14.8% of tree growth but for the dry site only 5.9% (February temperature).
As previous studies have shown (Bridge et al., 1990; Pilcher et al., 1995; Linderholm et al., 2002), there are difficulties with measurement and cross-dating of trees growing on wet soils (peatlands) not only among trees but also between radii from a single tree. This has been explained by the formation of compression wood in varying directions within the tree (Schweingruber, 2007) due to wind and unstable ground (i.e. peat), as well as ethylene-induced formation of reaction wood in flooded trees. Flooding also induces the formation of short, thick-walled rounded tracheids (generally resembling those in compression wood), surrounded by intercellular spaces (Kozlowski, 1997). A clear boundary can exist between earlywood and latewood, representing a false tree ring (Fritts, 2001). Also, most coniferous tree species produce resin ducts as a reaction to environmental stress (Gartner, 2007; Schweingruber, 2007). Resin duct density is an indicator of water stress, where irrigation increases the proportion of resin ducts in earlywood (Rigling et al., 2003), complicating the distinguishing of tree rings. For these reasons, in the study of tree-ring series only the best cores, i.e. those from 25 of the 60 cored trees, were measured and used for building the chronology. For the dry site only two trees were not included in further studies.
The sites were located rather close to each other and thus climatic factors could be expected to be similar. However, there are only a few cases when both chronologies showed a significant correlation with the same climate parameters. A significant influence of yearly mean temperature is a characteristic feature for pines growing in northern regions (Lindholm et al., 2000). Another characteristic feature is a significant positive influence of February mean temperature on pine growth, which has been observed in previous studies in Latvia (Elferts, 2008; Zunde et al., 2008), Poland (Cedro, 2001), Estonia (Parn, 2003), and Lithuania (Vitas, 2004). Scots pine is susceptible to winter and spring frosts. The significant relation with February temperature could be explained by a deeper frozen soil layer, which can increase the time period needed for the soil to thaw in spring. The same explanation might be offered for a positive influence of dormant-period mean temperature (Rydin & Jeglum, 2006) on pines on the dry and wet sites.
The influence of precipitation on pine growth on dry and wet soil is of dissimilar character. Pines growing on dry soil are positively influenced by yearly precipitation and growing-period precipitation. In the growing period, when temperatures are higher, especially in June and July (Fig. 2), transpiration is intensified and there is a need for additional moisture. Also in Southern Finland (Lindholm et al., 2000) and Poland (Cedro, 2001) pines growing on dry soils showed a positive relation to precipitation sum in summer months. Lack of a relationship between precipitation of most months and dry soil chronology might be explained by optimal moisture conditions for pine growth in a particular site (Linderholm, 2001).
The same explanation might be true for the trees growing at fen edges, which showed a positive response to July temperature. The high July temperature probably favours evapotranspiration and therefore the growth of trees, as observed for the Scots pines growing on alluvial terraces along Alpine rivers (Polacek et al., 2006).
Trees growing on peatlands are highly dependent on the depth and fluctuations of the water table, and precipitation and temperature regulate the water table depth. In addition, there might be a lag in the response of the water table to changing climate conditions (Linderholm, 2001). The growth of Scots pine is much more dependent on prior growth, especially for pines affected by water stress (Weber et al., 2007). Thus, pines growing on the wet soil showed negative responses mainly to previous-year and October climate parameters. A negative response can occur via bud and needle formation for the next year and therefore affect photosynthesis. A high yearly water level suppresses needle formation in coniferous trees and often inhibits bud initiation. Under anaerobic conditions, the activity of several metabolic pathways is suppressed or altered. Soil inundation affects not only the synthesis of carbohydrates but also their transport to meristematic sinks and their utilization in metabolism and production of new tissues. Shifts occur also in protein, organic acid, and lipid metabolism (Kozlowski, 1997). Especially October is a very important month for peatland pines, because at that time sugars are splitting to lipids in the tree (Lebedeva, 1967). The lag effect, which is characteristic of evergreen coniferous tree species in temperate climates, can obscure the response of pine to current moisture conditions (Weber et al., 2007). The low growth response to precipitation during the growing period may also suggest that there is sufficient water available.
In the analysis of peatland pine growth response to climate it is very important to examine water level data. Unfortunately, for the Engure fen sites this type of data are lacking. Water level records in Lake Engure cover only a 30-year period (from April to October, in some years to August), which is too short for reliable interpretation of results.
Despite the fact that the two chronologies had a significant correlation with climate parameters (seven for the wet site and nine for the dry site), the explained variation of tree-ring width was very low: 5.9% for the dry site and 14.8% for the wet site. As Latvia is not on the distribution border of Scots pine where a higher relation with climatic factors is expected (Schweingruber et al., 1990), other internal and external factors likely have a stronger influence on the radial growth of Scots pine.
The authors would like to thank Guntis Brumelis for revising the language of the paper. This study was performed with financial support of the European Social Fund and Latvian Council of Science (project 'Effects of Climate Change on the Nature of Latvia'). Climate data were obtained from the Latvian Environment, Geology and Meteorology Centre.
Agren, J. & Zackrisson, O. 1990. Age and size structure of Pinus sylvestris population on mires in central and northern Sweden. J. Ecol., 79, 1049-1062.
Agren, J., Isaksson, L. & Zackrisson, O. 1983. Natural age and size of Pinus sylvestris and Picea abies on a mire in the inland part of northern Sweden. Holarct. Ecol., 6, 228-237.
Biondi, F. & Waikul, K. 2004. DENDROCLIM2002: A C++ program for statistical calibration of climate signals in tree-ring chronologies. Comput. Geosci., 30, 303-311.
Bitvinskas, T. 1978. Habitat and climatic factors influence on dynamic and rhythm of radial growth of forests in Lithuanian SSR. In Usloviya sredy i radial'nyj prirost derev'ev, pp. 10-18. Institut Botaniki Litovskoj SSR, Kaunas (in Russian).
Boggie, R. 1972. Effect of water-table height on root development of Pinus concorta on deep peat in Scotland. Oikos, 23, 304-312.
Bridge, M. C., Haggart, B. A. & Lowe, J. J. 1990. The history and paleoclimatic significance of subfossil remains of Pinus sylvestris in blanket peats from Scotland. J. Ecol., 78, 77-99.
Buss, K. 1981. Meza ekologija un tipologija. Zinatne, Riga (in Latvian).
Cedro, A. 2001. Dependence of radial growth of Pinus sylvestris L. from western Pomerania on the rainfall and temperature conditions. Geochronometria, 20, 69-74.
Cedro, A. 2006. Comparative dendroclimatological studies of the impact of temeperature and rainfall on Pinus nigra Arnold and Pinus sylvestris in northwestern Poland. Baltic Forestry, 12(1), 110-115.
Elferts, D. 2007a. Scots pine pointer-years in northwestern Latvia and their relationship with climatic factors. Acta Univ. Latviensis, 723, 163-170.
Elferts, D. 2007b. Influence of climatic factors on the radial growth of Scots pine on a dune island of Ragana mire. In Climate Change in Latvia (Klavins, M., ed.), pp. 186-192. LU Akademiskais apgads, Riga.
Elferts, D. 2008. Influence of climatic factors on the radial growth of Scots pine Pinus sylvestris L. in western Latvia on dry soils. Summary of the Doctoral thesis. University of Latvia, Riga.
Fritts, H. C. 2001. Tree Rings and Climate. Blackburn Press, Caldwell, New Jersey.
Gartner, H. 2007. Glacial landforms, tree rings: dendrogeomorphology. In Encyclopedia of Quaternary Sciences, Vol. 2 (Elias, S. A., ed.), pp. 979-988. Elsevier.
Hokka, H. & Ojansuu, R. 2004. Height development of Scots pine on peatlands: describing change in site productivity with a site index model. Can. J. For. Res., 34, 1081-1092.
Holmes, R. L. 1983. Computer-assisted quality control in tree-ring dating and measurement. Tree Ring Bull., 43, 69-78.
Holmes, R. L. 1999. Dendrochronological Program Library (DPL). User's Manual. Laboratory of Tree-Ring Research, University of Arizona, Tucson, Arizona, USA.
Kozlowski, T. T. 1997. Responses of woody plants to flooding and salinity. Tree Physiol. Monogr., 1, 1-29.
Laanelaid, A. 1982. Radial increment of bog pines and climatic changes. In Peatland Ecosystems. Researches into the Plant Cover of Estonian Bogs and Their Productivity. Estonian Contribution to the International Biological Programme, No. 9, pp. 135-146. Tallinn.
Laanelaid, A. & Eckstein, D. 2003. Development of a tree-ring chronology of Scots pine (Pinus sylvestris L.) for Estonia as a dating tool and climatic proxy. Baltic Forestry, 9(2), 76-82.
Lebedeva, N. V. 1967. Dynamics of starch accumulation in spears of pine in drained and natural peatland. In Priroda bolot i metody ikh issledovanij, pp. 74-78. Nauka, Leningrad (in Russian).
Linderholm, H. W. 2001. Climatic influence on Scots pine growth on dry and wet soils in the central Scandinavian mountains, interpreted from tree-ring widths. Silva Fenn., 35, 415-424.
Linderholm, H. W., Moberg, A. & Grudd, H. 2002. Peatland pines as climate indicators? A regional comparison of the climatic influence on Scots pine growth in Sweden. Can. J. For. Res., 32, 1400-1410.
Linderson, H. 1992. Dendroclimatological investigation in Southern Sweden. In Proceedings of the International Dendrochronology Symposium "Tree Rings and Environment", Ystad, South Sweden, 3-9 September 1990 (Eggertson, O., ed.), pp. 198-201. Lund University, Department of Quaternary Geology, Lund.
Lindholm, M., Lehtonen, H., Kolstrom, T., Merilainen, J., Eronen, M. & Timonen, M. 2000. Climatic signals extracted from ring-width chronologies of Scots pines from the northern, middle and southern parts of boreal forest belt in Finland. Silva Fenn., 34, 317-330.
MacDonald, S. E. & Yin, F. 1999. Factors influencing size inequality in peatland black spruce and tamarack: evidence from post-drainage release growth. J. Ecol., 87, 404-412.
Morgan, G. A., Leech, N. L., Gloeckner, G. W. & Barrett, K. C. 2004. SPSS for Introductory Statistics: Use and Interpretation. Lawrence Erlbaum Associates, Mahwah.
Ohlson, M. 1995. Growth and nutrient characteristics in bog and fen populations of Scots pine (Pinus sylvestris). Plant Soil, 172, 235-245.
Ohlson, M. & Zackrisson, O. 1992. Tree establishment and microhabitat relationship in north Swedish peatlands. Can. J. For. Res., 22, 1869-1877.
Pakalne, M. & Kalnina, L. 2005. Mire ecosystems in Latvia. In Moore--von Sibirien bis Feuerland/Mire--from Siberia to Tierra del Fuego (Steiner, M., ed.), pp. 147-174. Biologiezentrum der Oberosterreichischen Landesmuseen, Linz, Austria.
Parn, H. 2003. Radial growth response of Scots pine to climate under dust pollution in Northeast Estonia. Water Air Soil Poll., 144, 343-361.
Pilcher, J. R., Baillie, M. G. L., Brown, D. M., McCormac, F. G., MacSweeny, P. B. & McLawrence, A. S. 1995. Dendrochronology of subfossil pine in the north of Ireland. J. Ecol., 83, 665-671.
Polacek, D., Kofler, W. & Oberhuber, W. 2006. Radial growth of Pinus sylvestris on alluvial terraces is sensitive to water-level fluctuations. New Phytol., 169, 299-308.
Pyateckij, G. E. 1963. Growth and development of forest stands on drained fens in south Karelia. Doklady soveshchaniya po geobotanicheskomu issledovaniyu bolot severo-zapada SSSR. Trudy po botanike, 7, 306-315 (in Russian).
Richardson, D. M. & Rundel, P. W. 2000. Ecology and biogeography of Pinus, an introduction. In Ecology and Biogeography of Pinus (Richardson, D. M., ed.), pp. 3-46. Cambridge University Press, Cambridge.
Rigling, A., Bruhlhart, H., Braker, O. U., Forster, T. & Schweingruber, F. H. 2003. Effects of irrigation on diameter growth and vertical resin duct production in Pinus sylvestris L. on dry sites in the central Alps, Switzerland. Forest Ecol. Manage., 175, 285-296.
Rinn, F. 1996. TSAP--Reference Manual. Frank Rinn, Heidelberg, Germany.
Rydin, H. & Jeglum, J. 2006. The Biology of Peatlands. Oxford University Press, Oxford.
Sarkkola, S., Hokka, H. & Penttila, T. 2004. Natural development of stand structure in peatland Scots pine following drainage: result based on long-term monitoring of permanent sample plots. Silva Fenn., 38, 405-412.
Schweingruber, F. H. 1988. Tree Rings. Basics and Applications of Dendrochronology. Reidel, Dordrecht, Netherlands.
Schweingruber, F. H. 2007. Wood Structure and Environment. Springer-Verlag, Berlin.
Schweingruber, F. H., Kairiukstis, L. & Shiyatov, S. 1990. Sample selection. In Methods of Dendrochronology: Applications in the Environmental Sciences (Cook, E. R. & Kairiukstis, L. A., eds), pp. 23-35. Kluwer Academic Publishers, Dordrecht.
Skudra, P. J. 1982. Climatic factors influence on the radial growth of coniferous trees. Trudy LSHA (Latvijskoj sel'skokhozyajstvennoj akademii), 58-65 (in Russian).
Spalte, E. 1975. Meteorologisko faktoru ietekme uz parastas priedes radialo pieaugumu. Jaunakais mezsaimnieciba, 18, 46-53 (in Latvian).
Spalte, E. 1985. Pastavigo summu metode un tas izmantosana mezkopibas un dendrohronologijas petijumos. Jaunakais mezsaimnieclba, 27, 34-10 (in Latvian).
Vasander, H. 1996. Peatlands in Finland. Finnish Peatland Society, Helsinki.
Viksne, J. 1997. Engure--the Lake of Birds. Riga.
Vitas, A. 2004. Dendroclimatological research of Scots pine (Pinus sylvestris L.) in the Baltic coastal zone of Lithuania. Baltic Forestry, 10(1), 65-71.
Vitas, A. & Erlickyte, R. 2007. Influence of droughts to the radial growth of Scots pine (Pinus sylvestris L.) in different site conditions. Baltic Forestry, 13(1), 10-16.
Weber, P., Bugmann, H. & Rigling, A. 2007. Radial growth responses to drought of Pinus sylvestris and Quercuspubescens in an inner-Alpine dry valley. J. Veg. Sci., 18, 777-792.
Zalitis, P. P. 1967. Relationship between radial growth of pine and melioration intensity in sedge reed habitat. Les i sreda, 104-118 (in Russian).
Zalitis, P. P. 1968. Dynamics of the daily mean radial growth of pine and spruce in the drained silvicultural sedge-reed habitat. Voprosy gidrolesomelioracii, 127-167 (in Russian).
Zunde, M., Briede, A. & Elferts, D. 2008. The influence of climatic factors on the radial growth of Scots pine (Pinus sylvestris) in Western Latvia. Proc. Latv. Acad. Sci., 62, 120-128.
Iluta Dauskane [mail] and Didzis Elferts
Faculty of Biology, University of Latvia, Kronvalda Blvd. 4, LV-1010 Riga, Latvia
[mail] Corresponding author, firstname.lastname@example.org
Received 30 September 2010, revised 11 January 2011
Table 1. Correlation between climate parameters and dry and wet soil site chronologies. Only statistically significant ([alpha] = 0.05) correlation coefficients (r) are shown Parameter Dry soil site Wet soil site Precipitation Previous year -0.297 October -0.264 February 0.193 Yearly 0.197 Growing period 0.200 Temperature January 0.220 February 0.256 0.249 March 0.296 July 0.206 Winter 0.279 Yearly 0.309 0.256 Dormant period 0.280 0.229 Growing period 0.203
|Printer friendly Cite/link Email Feedback|
|Author:||Dauskane, Iluta; Elferts, Didzis|
|Publication:||Estonian Journal of Ecology|
|Date:||Sep 1, 2011|
|Previous Article:||Re-evaluation of stand indicators for the assessment of the representativity status of the Natura 2000 habitat type forests/Loodusdirektiivi...|
|Next Article:||Effect of climate on extreme radial growth of Scots pine growing on bogs in Latvia/Kliima moju hariliku manni ekstreemsele radiaalkasvule Lati...|