MAŽALAPĖ LIEPA (Tilia cordata Mill.) LIETUVOJE: FENOTIPINĖ ĮVAIROVĖ IR MODALINIŲ MEDYNŲ NAŠUMAS ; SMALL-LEAVED LIME (Tilia cordata Mill.) IN LITHUANIA: PHENOTYPICAL DIVERSITY AND PRODUCTIVITY OF MODAL STANDS
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MAŽALAPĖ LIEPA (Tilia cordata Mill.) LIETUVOJE: FENOTIPINĖ ĮVAIROVĖ IR MODALINIŲ MEDYNŲ NAŠUMAS ; SMALL-LEAVED LIME (Tilia cordata Mill.) IN LITHUANIA: PHENOTYPICAL DIVERSITY AND PRODUCTIVITY OF MODAL STANDS

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LITHUANIAN UNIVERSITY OF AGRICULTURE Loreta Semaškien ė SMALL-LEAVED LIME (Tilia cordata Mill.) IN LITHUANIA: PHENOTYPICAL DIVERSITY AND PRODUCTIVITY OF MODAL STANDS Summary of doctoral dissertation Biomedical sciences, forestry (14B) Kaunas, 2006 This doctoral dissertation has been accomplished during the period of 1995-2006 in the Department of Forestry at the Lithuanian University of Agriculture. The dissertation will be defended externally. Scientific consultant: LAS expert member, Prof. Dr. Habil. Remigijus Ozolin čius (Lithuanian Forest Research Institute, biomedical sciences, forestry - 14B). Scientific supervisor: Ass. Prof. Dr. Mindaugas Navasaitis (Lithuanian University of Agriculture, biomedical sciences, forestry - 14B) (1995-2004). The dissertation will be defended in the Council of Forest Science at the Lithuanian University of Agriculture: Chairman: Prof. Dr. Habil. Edvardas Riepšas (Lithuanian University of Agriculture, biomedical sciences, forestry - 14B). Members: Prof. Dr. Habil. Antanas Juodvalkis (Lithuanian University of Agriculture, biomedical Prof. Dr. Habil. Juozas Ruseckas (Lithuanian Forest Research Institute, biomedical sciences, forestry - 14B). Dr. Audrius Skridaila (Vilnius University, biomedical sciences, botany - 04B). Prof. Dr. Habil.

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LITHUANIAN UNIVERSITY OF AGRICULTURE               Loreta Semakien ė      SMALL-LEAVED LIME ( Tilia cordata Mill.) IN LITHUANIA: PHENOTYPICAL DIVERSITY AND PRODUCTIVITY OF MODAL STANDS     Summary of doctoral dissertation Biomedical sciences, forestry (14B)               Kaunas, 2006  
 
 This doctoral dissertation has been accomplished during the period of 1995-2006 in the Department of Forestry at the Lithuanian University of Agriculture.  The dissertation will be defended externally.  Scientific consultant: LAS expert member, Prof. Dr. Habil. Remigijus Ozolin č ius (Lithuanian Forest Research Institute, biomedical sciences, forestry - 14B).  Scientific supervisor: Ass. Prof. Dr. Mindaugas Navasaitis (Lithuanian University of Agriculture, biomedical sciences, forestry - 14B) (1995-2004).  The dissertation will be defended in the Council of Forest Science at the Lithuanian University of Agriculture:  Chairman: Prof. Dr. Habil. Edvardas Riepas (Lithuanian University of Agriculture, biomedical sciences, forestry - 14B).  Members: Prof. Dr. Habil. Antanas Juodvalkis (Lithuanian University of Agriculture, biomedical sciences, forestry - 14B). Prof. Dr. Habil. Juozas Ruseckas (Lithuanian Forest Research Institute, biomedical sciences, forestry - 14B). Dr. Audrius Skridaila (Vilnius University, biomedical sciences, botany 04B). -Prof. Dr. Habil. Vida Stravinskien ė  (Vytautas Magnus University, biomedical sciences, ecology and environmental studies - 03B).  Opponents: Prof. Dr. Habil. Romualdas Juknys (Vytautas Magnus University, biomedical sciences, forestry - 14B). Prof. Dr. Habil. Eugenija Kup č inskien ė  (Lithuanian University of Agriculture, biomedical sciences, forestry - 14B).       The dissertation is intended for public examination of the Council of Forest Science on 26 th  of May 2006, at 14 p.m. at the Assembly Hall of the Department of Forest Management, of the Lithuanian University of Agriculture.  Address:  Lithuanian University of Agriculture  Studentu 11, LT-53067 Akademija, Kaunas district, Lithuania.  Phone: (370) 37 752254, Fax: (370) 37 397500. Summary of the doctoral dissertation was distributed on 26 th of April, 2006. The doctoral dissertation is available at the libraries of the Lithuanian University of Agriculture and the Lithuanian Forest Research Institute.    
 
 
LIETUVOS EM Ė S Ū KIO UNIVERSITETAS                 Loreta Semakien ė      MAALAP Ė LIEPA ( Tilia cordata Mill.) LIETUVOJE: FENOTIPIN Ė  Į VAIROV Ė IR MODALINI Ų MEDYN Ų NAUMAS    Daktaro disertacijos santrauka Biomedicinos mokslai, mikotyra (14 B)                Kaunas, 2006  
 
 
 Disertacija rengta 1995-2006 metais Lietuvos em ė s ū kio universiteto Mikininkyst ė s katedroje. Disertacija ginama eksternu.   Mokslinis konsultantas: LMA narys ekspertas, prof. habil. dr. Remigijus Ozolin č ius (Lietuvos mik ų  institutas, biomedicinos mokslai, mikotyra - 14 B).  Mokslinis vadovas: Doc. dr. Mindaugas Navasaitis (Lietuvos em ė s ū kio universitetas, biomedicinos mokslai, mikotyra - 14 B) (1995-2004 m.).   Disertacija ginama Lietuvos em ė s ū kio universiteto Mikotyros mokslo krypties taryboje:  Pirmininkas: Prof. habil. dr. Edvardas Riepas (Lietuvos em ė s ū kio universitetas, biomedicinos mokslai, mikotyra - 14 B).  Nariai: Prof. habil. dr. Antanas Juodvalkis (Lietuvos em ė s ū kio universitetas, biomedicinos mokslai, mikotyra - 14 B). Prof. habil. dr. Juozas Ruseckas (Lietuvos mik ų institutas, biomedicinos mokslai, mikotyra - 14 B).  Dr. Audrius Skridaila (Vilniaus Universitetas, biomedicinos mokslai, botanika - 04B) Prof. habil. dr. Vida Stravinskien ė  (Vytauto Didiojo universitetas, biomedicinos mokslai, ekologija ir aplinkotyra - 03B).  Oponentai: Prof. habil. dr. Romualdas Juknys (Vytauto Didiojo universitetas, biomedicinos mokslai, mikotyra - 14 B). Prof. habil. dr. Eugenija Kup č inskien ė  (Lietuvos em ė s ū kio universitetas, biomedicinos mokslai, mikotyra - 14 B).      Disertacija bus ginama vieame Mikotyros mokslo krypties tarybos pos ė dyje 2006 m. gegu ė s m ė n. 26 d. 14 val. Lietuvos em ė s ū kio universitete, Mikotvarkos katedros pos ė di ų  sal ė je.  Adresas:  Lietuvos em ė s ū kio universitetas  Student ų g. 11, LT-53067 Akademija, Kauno raj., Lietuva.  Tel. (8-37) 752254, faks. (8-37) 397500. Disertacijos santrauka isiuntin ė ta 2006 m. balandio m ė n. 26 d. Disertacij ą  galima peri ū r ė ti Lietuvos em ė s ū kio universiteto ir Lietuvos mik ų  instituto bibliotekose.    
 
 
INTRODUCTION  In Lithuanian forests there are 25 tree species of natural origin (Navasaitis, 2003), however, foresters are mostly focused on several of them providing the greatest economic value. Seeking to preserve natural environment, it is important to cherish not only prevailing, but also less spreaded species, especially broadleaved. Broadleaved forests consisting of oak, ash, elm, maple, hornbeam and lime stands cover only about 5.4% of the whole forest area in the Republic. They are described as the most complicated plant communities in respect to their phytocoenotic composition and structure. At present the studies of less widespread and threatened tree species become ever more important on the international scale, because they provide new information on species evolution (Wagner, 1995). Thus, the main goal of genetic resources conservation was raised by FAO Plant Genetic Resources Institute (EUFORGEN) - to conserve sufficient genetic diversity ensuring the evolution of species and populations under changing conditions (Franc Alain, 1997). Rare tree species are important from the viewpoint of increasing biological diversity and sustainability of forest ecosystems. In Lithuanian forests only one species of genus - small-leaved lime ( Tilia cordata Mill.)  is natural. No thorough studies have been carried out in lime stands. Only some descriptive works were published (Minkevi č ius, 1958; Juodvalkis,1963, 1965; Snarskis, 1968; Labanauskas, 1971, 1973; Oni ū nas,  1979;  Grigas, 1986; Navasaitis, 2004). Only some existing phenotypical forms and hybrids are mentioned, however, phenotypical differences between them are not described. Many applied works and recommendations are announced, however, research on morphological, biological, ecological properties, phenotypical forms of small-leaved lime have not been carried out in Lithuania until now. In some publications several varieties and forms of small-leaved lime are mentioned, but not always their growth location is provided, thus it is often not clear if the varieties were found in Lithuania (Navasaitis, 2004). Although systematically legalized (Labanauskas, 1971, 1973) phenotypic forms of small-leaved lime in Lithuania are described in different decorative plantations - parks of old estates, city streets and parks, private gardens, there are no data about small-leaved lime phenotypical diversity, stand productivity in Lithuanian dendrological or forestry literature. Many characteristics of the species phenotypical, biological and ecological properties in Lithuanian conditions are not analysed and described. Until now site productivity classes of lime stands have been determined by site productivity scale for birch (Lietuvos mikotvarkos taisykl ė s, 2003). In Lithuania the productivity and growth of lime stands have not been analysed, information on the productivity of lime stands is almost absent. Study aim  was to determine the distribution of lime stands in Lithuania, estimate their productivity and phenotypic variation. To achieve this aim, the following objectives were raised:  to analyse distribution of lime stands in different natural forest regions;  to study distribution of lime stands in different growth sites;  to analyse variation of phenotypic traits in forests, different natural forest regions, different sites;  to study seasonal development of small-leaved lime and to describe phenological diversity of the species.  to design yield models of modal lime stands. Novelty. For the first time distribution of lime stands in different natural forest regions of Lithuania has been analysed. For the first time studies of the phenotypical diversity were conducted, phenotypical diversity in natural stands has been analysed. Phenological forms of small-leaved lime were singled out, their development differences were justified. Yield models for all lime stand sites and site productivity scale for lime stands were designed. Theoretical and practical value. For the first time data on the diversity of phenotypical traits and on the influence of environmental factors on phenotypical indices of lime trees were analysed in Lithuanian stands of natural origin. The data may be applied to estimate the possibilities of lime
 
 
growth in different conditions, forecasting stand productivity. The data on phenotypic diversity may be important to preserve genetic diversity of naturally growing lime stands. For the first time the distribution of lime stands, their species composition in natural forest regions of Lithuania and in different sites were analysed. Yield models of modal stands and site productivity scales for lime stands were designed.  Approval of the research work. The main research findings were published in 2 prereviewed scientific articles and in 5 proceedings of conferences. The main  statements and findings of the research work were presented and discussed at the international scientific conference Forest Growing Problems and Achievements Moving Towards Sustainable Forestry (Akademija, 2003) and Republican Scientific Conferences Lithuanian Biological Diversity (condition, structure, protection) (Vilnius, 2003), Safety of Man and Nature (Akademija, 2003, 2004). Volume and structure of the work. The dissertation is written in Lithuanian. It consists of seven main parts: introduction, literature review, materials and methods, results, conclusions, references and appendixes. The dissertation comprises 200 pages, including 122 tables, 91 figures and 232 literature sources.  MATERIALS AND METHODS  Phenological observations . Phenological observations of small-leaved lime in 2001-2003 were carried out in the Central Lithuania (Obelyn ė and Kama forest - Kaunas distr.). Observations were carried out on 139 middle-aged (50-60 yr.), normally developed, healthy, open-growth, fruiting small-leaved limes. Studies were carried out taking into account individual seasonal development peculiarities of each tree. Phenological phases were recorded according to methodological guidelines (Nacevi č ius, 1975, Булыгин , 1976, 1979, Бейдеман , 1960, 1974). On the expiration of fast spring development, observation was performed 3 times a week, while in the autumn-winter-spring dormancy period observations were conducted 2-3 times per month (Navasaitis, 1980). During intensive growth and development of buds and leaves, as well as during flowering trees were observed every day. Flowering abundance was assessed during phenological observations, in the phase of mass flowering, while fruiting abundance - in the period of mass fruit maturation according to V.Kappers ( Каппер , 1915) scale. Data of meteorological conditions (mean air temperatures and the sum of efficient temperatures) were calculated according to the data of the Kaunas Meteorological Station (in 2001-2003). Having conducted phenological observations, calendar dates were changed by relative continuous numbers (started since 1 March - 03.01=1, 03.02=2 and 04.01=32, and so on). The method of linear correlation was applied for the interrelations of phenological phases. Cluster analysis was selected to group the observed trees according to the beginning time of phonological phases. The similarity of individuals was evaluated according to Euclids interdistance between individuals. The means of clusters were compared by the method of single-factor dispersion analysis (ANOVA). According to the calculated values of Fishers criterion (F), differences in mean values of clusters were ascertained under 0.05 significance level ( Č ekanavi č ius, Murauskas, 2001, 2002). Phenotypic diversity . Phenotypic diversity of small-leaved lime was studied in all natural forest regions (NFR) of Lithuania. Study plots were selected in all more important (Nc, Nd, c, d, Ld, Lf*) sites of lime stands, in mature (7-8 age class) lime stands of average stocking level (0.6-0.7) and prevailing site productivity class (Ia-I), where lime trees in the species composition comprised not less than 40%. * Humidity of soil: N  normal,   slopes, L  temporarily overmoistured; Fertility of soil: c  fertile, d  very fertile, f  especially fertile. In lime stands 104 temporary 500m 2 in size study plots were selected, which were allocated in typical, homogeneous by stand species composition and site conditions areas. For the studies, A class (Kraft class 2) lime trees were chosen. Number of observation plots: in emai č iai highland (1 NFR) - 5; in NFR of the central lowland subregion of Northeastern Lithuania (2A) - 24; in the Auktai č iai highland subregion (2B) -
 
 
16; in the Coastal lowland (3 NFR) - 14 plots; in NFR of the lowland subregion in South Lithuania (4A) - 31 and in the highland subregion (4B) - 14 plots (Fig. 1).
Fig. 1. Distribution of observation plots  In the plots dendrometric indices were measured (H, D, A), qualitative and diversity traits were assessed. In the work, the following phenotypic traits are analysed: ƒ  tree height, diameter, height to live branches, height to dead branches, crown diameter. ƒ  crown width, thickness of lower branches, branch angle, number of dead branches, stem form, type of crookedness, trunk cross-section, snagginess, bifurcation, stem expression in the crown. ƒ  crown shape, form of bark pattern, bark colour, colour of shoots. The strength and variability of relationships is estimated having calculated the criterion of traits independence χ 2 , which reveals whether the traits are statistically significant ( Č ekanavi č ius, Murauskas, 2001, 2002). Analysis of the distribution of lime stands and the productivity of modal stands. Studying the distribution of lime stands in Lithuania and ascertaining their distribution in natural forest regions, stand data basis compiled by the Lithuanian Forest Management and Inventory Institute was used. The data of lime stands were grouped by sites and age classes, so that it is easier to calculate the area of lime stands of a corresponding age class growing in one or another site. Mean stand species composition was also calculated by sites, age classes and natural forest regions. Data of 17748 stands growing on an area of 37889 ha were used. In 3004 stands lime trees (4610 ha) prevail. RESULTS G ENERAL CHARACTERISTICS OF L ITHUANIAN LIME STANDS AND THEIR DISTRIBUTION   Having analysed forest inventory data, it was estimated that lime stands in Lithuania grow on an area of 4610 ha and comprise 0.24% of all forests. Stands, however, are small and randomly distributed on the territory of the country. Pure lime stands make up only 3.4% of the total area of lime stands. Stands containing only 4-5 parts of limes in their species composition prevail.
 
 
Average species composition of all lime stands (%) is as follows: 54% - lime, 10% - oak, 7% -aspen, 6% - birch, 5% - ash, 5% - spruce, 3% grey alder, 1% - red pine, 1% - black alder, 8% other tree species. The area of mixed stands containing lime trees comprises 33258 ha, their growing stock volume makes up 6019130 m 3 , volume per 1ha  181 m 3 ha -1 . Half of all Lithuanian lime stands are accumulated in the South Lithuanian natural forest region. In S ū duva-Nemunas lowland subregion are distributed 43%, while in Dz ū kai and S ū duva highlands subregion about 7.3% of all lime stands. Lime stands are mostly distributed in sites of normal humidity (N - 40%,  - 41%), less in temporarily overmoistured (L - 19%) sites. Very small plots are found in overmoistured (U - 0.1%) and boggy (P - 0.1%) soils. In slope sites (b, c, d) - on the banks of streams and rivers and washes are distributed 41% of the country lime stands, 59% grow in plain areas. In very infertile (a) and infertile sites (b) grow about 1%, in fertile (c) - 28%, in very fertile (d) - 62%, in exceptionally fertile (f) - 9% of all lime stands. Lime stands grow in soils of different mechanical structure (sand, gravel, clay). In the Coastal lowland region 70% of lime stands are distributed in slope sites on c and d trophotops, 20% - in sites of normal humidity, 10% - in temporarily overmoistured sites. In emai č iai highland region 55% of lime stands grow in slope sites, 28% in sites of normal humidity, the rest 17% are distributed in more moist sites Lc, Ld, Lf. In the Auktai č iai highland subregion of North-eastern Lithuania and in S ū duva highland subregion of South Lithuania lime stands prevail in Nc and c, as well as in Nd and d sites, in other sites grow about 11-12% of lime stands. In S ū duva-Nemunas lowland subregion of South Lithuania in slope sites grow about 33% of stands, 57% of lime stands grow on N hydrotope sites, from them 33% on site Nc. In the central lowland subregion of North-eastern Lithuania in slope sites grow 13% of lime stands, in sites of normal humidity - 36%, while in L hydrotope sites - 52% of lime stands. According to site humidity index may be distinguished coastal lowland region, in which 70% of lime stands are distributed in  hydrotope sites, and central lowland subregion of North-eastern Lithuania, where 52% of lime stands are rallied in L hydrotope sites. Having analysed the data by the method of multiple regression analysis, it was found that distribution of lime stands is mostly influenced by site humidity (hydrotope) (p=0.0004) and fertility (trophotop)(p=0.007). The drier is the site, the bigger area in all stands is occupied by lime stands. Climatic continentality has no impact on the distribution of lime stands (p=0.464).  P HENOTYPICAL DIVERSITY OF SMALL -LEAVED LIME ( T ILIA CORDATA  M ILL .)    AND FACTORS DETERMINING IT   Phenology In the Central Lithuania lime buds start to swell averagely on 04.04±7.4 day. The earliest swelling of buds in spring was recorded on 03.23 (aver. 03.29±4.5), while the latest  04.19 (aver. 04.12±3.6) (V=21%). Between trees with the earliest and the latest bud swelling 12.7±3.9 days phenological interval was recorded. According to bud swelling process, groups of limes with different beginning time of phases were distinguished (p<0.05). The buds of distinguished groups of trees swell at different time and may be called phenological forms. The early phenological form was recorded for 48%, late - 30% of lime trees. The beginning of bud bursting is considered to be the start of vegetative period. During bud burst leaves are developing very fast. In the Central Lithuania lime buds start to burst averagely on 04.26±8.5 day. The earliest bud bursting was recorded on 04.11, the latest  on 05.07. Mass bursting of buds starts on 04.30±1.5 (V=14.6%). 15% of the observed individuals with the earliest bud burst (04.24±0.9) are described as the early phenological form. Trees, the buds of which start to burst averagely on 04.26±0.8, are described as the intermediate phenological form (49%). Mass bursting of trees of the late phenological form (36%) starts the latest (05.02±0.9). Lime buds burst on 7.8±1.5 day (from the beginning of phase to its end), in different years bud burst time on an average varies (V=18.9%).
 
Following bud burst, starts an intensive growth of leaves. Foliation of lime trees starts at the end of April - beginning of May, averagely on 04.29±9.0 (V=15.0%). The earliest foliation of lime was recorded in April (04.16), the latest - in the middle of May (05.11). Phenological amplitude of the beginning of foliation of many years comprises 25 days, while in separate years  6-7 days  (6.3±1.5 days). The phase of mass foliation starts averagely on 05.03±9.0 (V=14%). Lime trees complete their foliation in May (05.07±9.8). An interval of 6-11 days is recorded between the earliest foliating and the latest foliating trees. This difference is constantly observed on individual trees. Having carried out cluster analysis according to mean dates of the beginning of foliation, mass period and complete foliation of lime trees, three clusters were distinguished (Fig. 2.).  12 11 10 9 8 7 6 5 4 3 2 1 0 Tree No.  V- late f. A  early f. N- intermediate f. Fig. 2. Groups of small-leaved lime according to the progress of foliation phase  Having analysed the data by ANOVA method, it was ascertained that mean values of clusters distinguished based on mean dates of foliation phenological phase periods differ (p<0.05). Groups of similar lime trees distinguished by cluster analysis may be called phenological forms according to the progress of foliation phase. To the early phenological form are described 42% of lime trees, intermediate form - 38%, late form - 20% of lime trees. When some trees have completed their foliation, bud burst of other lime trees has just started (Fig. 3). 62,5 71,0 62,0 70,5 61,5 7609,,50 61,0 69,0 60,5 68,5 60,0 68,0 59,5 6677,,50 59,0 66,5 58,5 A V 66,0 N A V N Groups Groups   A  early form; N- intermediate f.; V- late f. Beginning of foliation  Complete foliation   Fig. 3. Foliation of different phenological forms of small-leaved lime ( Tilia cordata Mill.)    
 
The first leaves take full size characteristic of the species in the middle of May - 05.12±8.8  (V=12.1%). Annual amplitude of the beginning of the phase is 7-8 days, that of many years - 23 days. The earliest date of the phase was registered on 05.02, the latest - on 05.25. Most leaves  (>50%) develop to the normal size in the middle of May - 05.18±7.7 (V=9.8%), while all the leaves fully develop at the end of May  05.21±8.0 (V=9.8%). Depending on meteorological conditions, the time of autumn leaf yellowing and intensity varies. Individual leaves begin to yellow at the end of summer, more yellowing leaves in tree crowns appear in September, on 09.01±8.1 (V=4.4%). Mass yellowing of leaves begins at the end of September  at the beginning of October, averagely on 09.29±7.1 (V=1.6-3.1) and become yellow until the middle of October (10.05±6.1). Autumn shedding of leaves begins on around 09.07±7.9 (V=4.2%), when the weather cools down and especially when average daily temperature falls down to +5 o C. Mass leaf shedding starts at the beginning of October, in the first-second decade of October (10.07±5.5). All the leaves fall down in October, on around 10.18±7.4 (V=3.3%). The end of leaf shedding is considered to be the end of the vegetative period of trees, while the period from bud burst to the end of leaf shedding is considered to be the vegetation period. The vegetation of lime in Lithuania ends averagely on 10.15±7.12 day. A strong correlation with mean air temperature is revealed (V=0.76). Vegetative period of small-leaved lime in the Central Lithuania according to the observation data lasts on an average about 172.5±4.4 days. Duration of the vegetative period of individual trees differs by 1.5-3 weeks. When buds are bursting, shoots start developing inside them. The first shoots finish their growth in May 05.20±6.0 (V=7.4%). Mass period of the phase starts at the end of May (05.27±4.6) and continues until June (06.07±3.4), when all lime shoots (90-100%) finish their development. The growth period of lime shoots is rather long. They grow intensively for a month, until leaves fully develop on them, buds form in leaf axils and on the top of shoots, the bark becomes suberified, and they acquire peculiar to the species colour. The beginning of suberification of shoots was registered on 07.11±3.9. Analysis shows that according to shoot suberification phase, early (35%), intermediate (19%) and late (45%) phenological forms of small-leaved lime are distinguished. Lime trees flower only after having completed foliation. In 2001-2003 observation period the earliest flowering of lime trees was recorded in the first decade of June  (06.08), the latest  at the beginning of July (07.05). All lime trees were flowering in the second part of June, on average - 06.21±6.0 (V=5.3%) (Table 1.).  Table 1. Beginning of small-leaved lime flowering in 2001-2003 (mean dates (X), mean standard error (m x ), standard deviation (S), variation coefficient (V,%), the earliest (F min ) and latest (F max ) dates and phenological amplitude (A fen ) Phenological phase Year X±m x S V,% F min F max A phen. 2001 06.21±0.17 2.00 1.76 06.19 06.25 6 Beginning of flowering 2002 06.11±0.19 2.18 2.11 06.08 06.15 7 2003 07.02±0.12 1.43 1.15 06.30 07.05 5 Average 06.21±1.09 6.0 5.31 06.08 07.05 27 2001 06.25±0.18 2.10 1.79 06.22 06.28 6 2002 06.17±0.15 1.78 1.62 06.15 06.21 6 2003 07.08±0.14 1.68 1.29 07.05 07.12 7 Average 06.26±1.07 6.0 5.08 06.15 07.12 27 2001 06.30±0.12 1.41 1.16 06.27 07.02 5 2002 06.21±0.14 1.64 1.44 06.19 06.24 5 2003 07.13±0.15 1.82 1.35 07.11 07.17 6 Average 07.01±1.15 6.2 5.04 06.19 07.17 28
Flowering
End of flowering  
 
 
Phenological flowering phase is the most distinctive among all seasonal development phases of small-leaved lime (Fig. 4.). Having carried out dispersion analysis of observation data, calculated based on mean dates of flowering beginning, mass flowering and its end F criterion shows that mean values of the distinguished clusters differ (p<0.05). These groups (clusters) may be called phenological forms of smallleaved lime according to flowering time: 51% of limes are described to the early form, 23% - to intermediate form, 26% - to the late phenological form.  10 9 8 7 6 5 4 3 2 1 0 Tree No.  A-Early form N-Intermediate V-Late form form Fig. 4. Similarity of small-leaved lime trees by flowering phase  The first nuts form on 06.30±6.6 (V=5.4%) and gradually proceed until the middle of July (07.09±6.8). Normal size the first nuts reach in two months (50.2±4.1), averagely on 08.02±4.2 (V=2.7%). Fully formed and mature fruits start to ripen at the end of August (08.26±7.5, V=4.16%), while all the nuts become ripe in the middle of September (09.08±7.7, V=3.98%). Since the beginning of flowering to full ripening lime fruits develop on an average 78.4±3.6 days (V=4.54%). Mature healthy fruits start falling at the end of September - beginning of October (10.05±5.4). Mass falling of nuts is observed in winter (01.14±9). According to the time of most phenological phases, it is possible to distinguish early, intermediate and late forms of small-leaved lime. The most interrelated are foliation and flowering phenological phases, the least interrelated are bud swelling and leaf shedding phases. Having carried out phenological observations, it was revealed that the beginning of bud swelling depends on the sum of efficient (above +5 o C) temperatures (R=0.86 - R=0.91). The period of bud burst phenological phase is characterized by high air temperature fluctuations. Comparing the sums of efficient temperatures, necessary for the bud burst of small-leaved lime of early, intermediate and late phenological forms, small, however, statistically significant (p<0.05) differences were recorded. The amount of the sum of efficient temperatures required for the foliation of early, intermediate and late phenological forms differs by about 20 o C (p<0.05). Shoot suberification time and speed are very closely related with the sum of efficient temperatures of the vegetation period (R=0.9). Trees of different phenological forms need different amount of the sum of efficient temperatures. In conclusion, different Lime forms (distinguished according to the time of flowering) need different amounts of efficient temperatures to achieve a certain development stage.