Electronic Journal of Polish Agricultural Universities (EJPAU) founded by all Polish Agriculture Universities presents original papers and review articles relevant to all aspects of agricultural sciences. It is target for persons working both in science and industry,regulatory agencies or teaching in agricultural sector. Covered by IFIS Publishing (Food Science and Technology Abstracts), ELSEVIER Science - Food Science and Technology Program, CAS USA (Chemical Abstracts), CABI Publishing UK and ALPSP (Association of Learned and Professional Society Publisher - full membership). Presented in the Master List of Thomson ISI.
2006
Volume 9
Issue 3
Topic:
Forestry
ELECTRONIC
JOURNAL OF
POLISH
AGRICULTURAL
UNIVERSITIES
Jelonek T. , Pazdrowski W. , Tomczak A. , Stypuła I. 2006. RADIAL AND AXIAL VARIABILITY OF THE PROPORTION OF SAPWOOD AND HEARTWOOD IN STEMS OF SCOTS PINE TREES (PINUS SYLVESTRIS L.) DEVELOPED IN CONDITIONS OF FORMER FARMLANDS AND TYPICAL FOREST SITES, EJPAU 9(3), #02.
Available Online: http://www.ejpau.media.pl/volume9/issue3/art-02.html

RADIAL AND AXIAL VARIABILITY OF THE PROPORTION OF SAPWOOD AND HEARTWOOD IN STEMS OF SCOTS PINE TREES (PINUS SYLVESTRIS L.) DEVELOPED IN CONDITIONS OF FORMER FARMLANDS AND TYPICAL FOREST SITES

Tomasz Jelonek1, Witold Pazdrowski1, Arkadiusz Tomczak1, Ireneusz Stypuła2
1 Department of Forest Utilization, University of Life Sciences in Poznań, Poland
2 Białogard Forest Division, Szczecinek Regional Directorate of State Forests RDSF, Poland

 

ABSTRACT

The study makes an attempt to ascertain radial and axial variability in the proportion of sapwood and heartwood in the stems of Scots pine trees which developed in different conditions of growth and development.

In general, pine trees growing in conditions of former farmlands were characterised by a greater proportion (in the forest site types which were taken under consideration) of heartwood and smaller proportion of sapwood than pine trees which developed in conditions of typical forest soils.

Both in the case of pines derived from the former farmlands and those that developed on typical forest soils, a greater proportion of heartwood was observed on the fresh coniferous forest (fresh coniferous forest) site type, while sapwood was found prevalent in pine trees which developed in conditions of the mixed fresh coniferous forest (mixed fresh coniferous forest) site type.

The authors found radial and axial irregularities in the process of heartwood formation in the stems of Scots pines which developed in conditions of the former farmlands and forest soils on fresh coniferous forest and mixed fresh coniferous forest against the background of biosocial classes. The vertical range of heartwood may be affected by a number of factors of which the tree crown appears to be the most important one.

It is further believed that the proportion of the sapwood zone and the rate and course of the heartwood formation process may be influenced by the size and the transpirational efficiency of tree crowns, development of water blockages in the conducting elements, tree biosocial position in the stand as well as the type of soil on which a given tree is growing.

A significant impact of the crown on the formation of the sapwood zone in tree trunks is confirmed by the obtained high determination coefficients R2 for the dependence of the mean width of the sapwood zone on the volume and surface area of crowns.

Key words: Scots pine, sapwood, heartwood, former farmlands, fresh coniferous forest, mixed fresh coniferous forest.

INTRODUCTION

In years 2002-2004, high consumption of, practically speaking, all timber products was observed in the UNECE region. Due to continued favourable economic trends, economists predict that growing economic tendencies will persist also in 2006 [17].

According to the above-mentioned source, China and the USA remain the main driving forces behind the observed growth with fairly good results also reported by Central and East European States.

Dziewanowski [4] maintains that there are very good conditions for the production of pine timber of the highest quality in Poland.

It is estimated that this year, the total of 27,665 million m3 of large timber will be harvested in the State Forests of which 11,465 million m3 is saw timber (including 268000 m3of special saw timber) and 12.642 million m3 of middle-sized wood [22]. It should be emphasized that nearly 73% of the harvested timber raw material is coniferous wood with pine as the indisputable leader. The significance of this important forest-forming species is enhanced by the National Program of Increasing Wooded Areas which is being realised in Poland [16].

Wood industry continues to declare growing demand for timber raw material of the highest quality, therefore it is necessary to seek new ways which would allow to utilise fully nature’s production potentials without disturbing balanced and rational forest economy. Ultimately, it should result in the production of timber raw material of the highest quality of predetermined purpose.

Depending on what the given timber raw material is intended for, the properties of its sapwood or heartwood may either be treated as an advantageous or disadvantageous trait [12]. For example, a wide sapwood zone is a desirable feature when timber is to be used for plywood production, whereas when it is to serve as raw material for the production of vats for the pharmaceutical and chemical industries, or various containers for the building industry, then heartwood is more desirable [ 9, 10, 11].

There is a widely held opinion concerning irregular formation of the heartwood in the stems of Scots pines [1, 20] as well as the correlation between sapwood and heartwood, on the one hand, and some biometric traits of trees and their crowns, on the other [3, 7].

This study makes an attempt to determine the variability in the proportions of sapwood and heartwood in the radial and axial cross sections of Scots pine (Pinus sylvestris L.) trees which developed in different growth conditions and factors affecting this changeability.

MATERIAL AND METHODS

The experimental material comprised wood of Scots pine (Pinus sylvestris L.) trees which developed in conditions of typical forest soils and former farmlands on the fresh coniferous forest and the mixed fresh coniferous forest site types in the Miastko Forest District which belongs to the Szczecinek Regional Directorate of State Forests (RDSF) (Fig. 1).

Figure 1. Location of the Miastko Forest District (collected from http://www.lasypanstwowe.gov.pl/mapy/index.htm)

Investigations were carried out in pine saw timber stands of the V age class.

On the established 0.5 ha test plots representative for each stand, the authors measured breast height diameters of all trees as well as heights proportionally to the numbers of trees in the adopted (2 cm) thickness degrees. The total of 10% of heights of all trees on the test plots was measured. On the basis of the obtained thickness-height characteristic of trees, using the Urich ll method [4], 12 model trees were selected (3 trees for each experimental surface).

Since biometric traits of the pine trees were also taken into consideration, the choice of mean sample trees was made on the basis of the determined thickness-height characteristics (according to Urich II) and Kraft’s biological classification (taking into account its first three classes, i.e. the main stand).

The model trees were felled and their trunks were cut into two meter sections and discs for the determination of selected traits of the wood macrostructure were cut out from the middle of each of them.

On the basis of measurements, widths of sapwood and heartwood zones on the radius of the excised discs were determined.

RESEARCH RESULTS

The obtained research results from the mean sample trees confirm the common view about the irregular formation of heartwood in the stems of Scots pine trees. This, in turn, results in the radial and axial (along the stem) differentiation in the proportion of heartwood in the cross section of tree trunks.

Since the occurrence of sapwood and heartwood in tree trunks is closely correlated with the size and efficiency of tree crowns and in an attempt to better understand these phenomena, the authors decided to enclose in this study the crown characteristics of the examined mean sample trees (Tab. 2) and explain their correlation with the width of sapwood and heartwood zones in the tree trunks of model trees (Figs. 5 and 6).

Mean proportions of sapwood and heartwood along the radius of the trunk cross section are presented in Table 1 and Figures 2 and 3.

Table 1. Mean percentage proportion of sapwood and heartwood across the radius of the cross section of a trunk segment

 

Forest soils

Former farmland

fresh coniferous forest

mixed fresh coniferous forest

fresh coniferous forest

mixed fresh coniferous forest

heartwood

sapwood

heartwood

sapwood

heartwood

sapwood

heartwood

sapwood

Whole trunk

37.9

62.1

43.2

56.8

38.9

61.1

46.6

53.4

Large-sized

53.0

47.0

58.1

41.9

58.4

41.6

63.5

36.5

Medium-sized

6.0

94.0

5.3

94.7

5.1

94.9

17.6

82.4

Pines which grew in conditions of the fresh coniferous forest site types on forest soils were characterised by a slightly higher (62.1%) share of sapwood and slightly lower (37.9%) proportion of heartwood in comparison with pines growing in condition of the former farmlands, where the proportions were, respectively 61.1% for sapwood and 38.9% for heartwood (Fig. 2).

Greater differences in the proportion of the two wood zones between Scots pines growing in conditions of the former farmlands and typical forest soils were found in the case of the slightly more fertile mixed fresh coniferous forest sites (Fig. 3).

Differences were also observed in the mean proportions of sapwood and heartwood across the radius between the analysed forest site types.

Despite the fact that fresh coniferous forest and mixed fresh coniferous forest sites provide optimal conditions for the growth of the examined tree species, the proportions of the two types of wood in the trunks of model trees differed significantly.

Both in the case of pines derived from the former farmlands and from typical forest soils, the proportion of heartwood was higher in trees derived from the mixed fresh coniferous forest sites, while that of sapwood – in pine trees which grew in fresh coniferous forest sites (Figs. 2 and 3).

It can, therefore, be said that the forest site type and tree growth conditions exert a significant influence on the process and rate of formation of heartwood in the trunks of Scots pines. In addition, the obtained results corroborate the hypothesis [2] about a more dynamic process of heartwood formation in trees growing in worse conditions of growth and development, in this case on a poorer site and the former farmlands.

Figure 2. Mean radial proportions of heartwood and softwood in Scots pines developed in conditions of the former farmlands and forest soils on fresh coniferous forest sites

   

Figure 3. Mean radial proportions of heartwood and softwood in Scots pines developed in conditions of the former farmlands and forest soils on mixed fresh coniferous forest sites

   

Since the proportion of heartwood and sapwood in tree trunks predetermines, to a certain degree, the possibilities of application and utilisation of the timber raw material, an attempt was also made in this study to estimate the radial proportion of the analysed wood zones in the large- and medium-sized timber raw material (Figs. 4, 5 and 8, 9).

The large-sized timber raw material, i.e. with the diameter up to 14 cm at the top end without bark, was characterised by a higher proportion in the trunks of model trees of heartwood than sapwood (Figs. 4 and 5).

Figure 4. Mean radial proportions of heartwood and softwood in the large-sized raw material of Scots pines developed in conditions of the former farmlands and forest soils on fresh coniferous forest sites sites

   

Figure 5. Mean radial proportions of heartwood and softwood in the large-sized raw material of Scots pines developed in conditions of the former farmlands and forest soils on mixed fresh coniferous forest sites

   

The highest radial proportion of heartwood (63.5%) on the trunk cross section was found in the stems of pines derived from the former farmlands in conditions of mixed fresh coniferous forest sites, while the smallest share of this zone (53%) was observed in typically forest pines which developed in conditions of fresh coniferous forest sites.

Proportions of sapwood were reversed to those of heartwood. Its highest proportions (47%) were determined in typically forest Scots pines which developed in conditions of fresh coniferous forest sites and the lowest (36.5%) – in pines derived from the former farmlands which developed on mixed fresh coniferous forest sites (Figs. 4 and 5).

It should be emphasised that the above-described proportions and quantities of the analysed wood zones appear to be somewhat atypical and differ from the commonly held opinion that the dynamics of heartwood formation and the proportion of heartwood is greater in trees growing in poorer site conditions [12]. Therefore, it is perhaps worth while considering the appropriateness of the classification on the forest site types on former farmlands.

In an attempt to interpret the obtained results, the authors decided to examine the relationship between the analysed traits and the crown area and volume of the model trees.

Figures 6 and 7 show the relationship between the average width of the sapwood and heartwood zones in tree stems and the volume and surface area of the model tree crowns.

The obtained high determination coefficients R2 for the relationship of the mean width of the sapwood zone and the crown volume (0.86) and the crown surface area (0.87) indicate a significant impact of the crown on the development of the sapwood zone in tree stems.

Lower determination coefficients were found for the correlation between the mean width of the heartwood zone and the crown volume and surface area, This may indicate the correctness of the hypothesis about the uneven heartwood formation in the stems of pines and point to some relationship between its formation and the development of water blockages [1, 23].

Table 2. Crown characteristics of Scots pines developed in conditions of former farmlands and forest soils in fresh coniferous forest and mixed fresh coniferous forest sites

Kraft class

Forest

Farmland

fresh coniferous forest

mixed fresh coniferous forest

fresh coniferous forest

mixed fresh coniferous forest

Vk [m3]

Pk [m2]

Vk [m3]

Pk [m2]

Vk [m3]

Pk [m2]

Vk [m3]

Pk [m2]

I

458.0

338.7

387.8

302.0

363.2

286.3

238.3

223.9

II

282.7

247.8

260.1

230.0

163.0

169.6

169.5

173.8

III

94.2

117.4

224.6

207.7

121.2

137.2

157.8

166.0

Mean

278.3

234.6

290.8

246.6

215.8

197.7

188.5

187.9

Vk – crown volume assumed as the volume of a cylinder
Pk – crown surface area assumed as the surface area of a cylinder

Figure 6. Correlation between the mean width of heartwood and sapwood zones and the crown volume of Scots pines developed in conditions of farmlands and forest soils

   

Figure 7. Correlation between the mean width of heartwood and sapwood zones and the crown surface area of Scots pines developed in conditions of farmlands and forest soils

   

The proportions of sapwood and heartwood were also analysed in the medium-sized timber raw material, i.e. with the diameter of 7 cm at the thinner (top) end of the bole without bark.

The medium-sized timber raw material was characterized by considerable proportions of sapwood ranging from 82% of the radius width in the case of pines developed in conditions of farmlands on mixed fresh coniferous forest sites to almost 95% of the radius width in the remaining model trees (Figs. 8 and 9).

A fairly large share of the heartwood zone and low share of the sapwood zone in pine trees developed in conditions of farmlands on mixed fresh coniferous forest sites deserves attention.

As in the case of the large-sized timber raw material, also here the most probable cause of this phenomenon can be attributed to the size and efficiency of the crown and disturbances in the water conduction resulting from changes in conducting elements.

Figure 8. Mean radial proportions of heartwood and softwood in the medium-sized timber raw material of Scots pines developed in conditions of the former farmlands and forest soils on fresh coniferous forest sites

   

Figure 9. Mean radial proportions of heartwood and softwood in the medium-sized timber raw material of Scots pines developed in conditions of the former farmlands and forest soils on mixed fresh coniferous forest sites

   

Figures 10 and 11 illustrate the radial distribution of heartwood and sapwood proportions along the stems of Scots pines taking into consideration their biosocial position in the stand.

The presented Figures illustrate fairly well the irregular distribution of heartwood and sapwood zones along the tree trunk.

The greatest differences in the share of the analysed wood zones along the trunks occurred in trees which belonged to the II Kraft class, i.e. in dominant trees (Fig. 10).

It is worth emphasising here that, in the majority of the analysed trees, the intersection of curves representing the proportion of sapwood and heartwood (50% of share on the radius) occurred slightly lower in the case of trunks derived from pines which developed in conditions of typical forest soils, despite the fact that, as a rule, these trees were higher in comparison with Scots pines developed on farmlands (Figs. 10 and 11).

It is quite likely that the process of dying of parenchymal cells runs somewhat slower in pine trees derived from typical forest soils than in those from former farmlands. Another explanation can be the size of the crown which (as a rule bigger in typical forest pine trees) may exert a significant influence on the development of the conducting zone of the tree trunk.

Another interesting observation was that, in poorer sites, the sapwood zone at the base of the tree trunk of trees from the I and II Kraft classes occupied the same area as the heartwood zone (Fig. 10 a and b), whereas in the remaining situations the share of the heartwood zone in the trunk butt end was higher than that of the sapwood zone (Fig. 10 c and d) which is understandable from the point of view of the trunk mechanics. Heartwood fulfils mechanical functions and its considerable proportion at the base of the stem is connected, among others, with the occurrence here of the strongest bending moment during winds.

The proportion of sapwood and heartwood up to the point of another intersection of curves, in the case of pine trees derived from typical forest soils and the former farmlands from the I Kraft class as well as from typical forest soils from the II Kraft class, is similar (Fig. 10 a and b).

Perhaps trees growing on the poorer site (fresh coniferous forest) but which occupy good biosocial positions in the stands (I and II Kraft classes) maintain a considerably bigger conducting area (sapwood) in order to preserve balance between the developed assimilation apparatus (crown) and the conducting part (sapwood).

Both the crown volume and surface area of these trees (Tab. 2) appear to corroborate this train of thought. This situation may further be affected by the quality and effectiveness of the conducting elements (tracheids) where for long periods of time no blockages are formed during water conduction along the trunk. This situation may contribute to the slowing down of the heartwood formation, which is especially visible in the case of pre-dominant trees in fresh coniferous forest (Fig. 10 a).

The most irregular course of the sapwood and heartwood zones along the trunk was observed in the pre-dominant trees, especially in pines derived from the former farmlands (Figs. 10 a and 11 a).

Figure 10. Percentage proportion of heartwood and sapwood in the stems of Scots pine trees (Pinus sylvestris L.) developed in conditions of former farmlands and forest soils in the fresh coniferous forest site type

a)
I Kraft class (pre-dominant)
    b)
II Kraft class (dominant)

c)
III Kraft class (co-dominant)
Point of intersection of curves of the proportion of sapwood and heartwood (forest)
Point of intersection of curves of the proportion of sapwood and heartwood (farmlands)

A regular course of the analysed zones occurred in co-dominant trees of the smallest crown sizes, i.e. in pine trees derived from typical forest soils (Figs. 10c, 11c). The process of heartwood formation occurred here gradually and uniformly, especially in pine trees which developed in conditions of typical forest soils.

Such course can be explained by the fact that the position of a co-dominant tree appears to be most stable in the stand and a given tree could occupy only this position in the community throughout its lifetime. It can also be supposed that with the change of the position the tree occupies it is not only the assimilation apparatus itself that undergoes transformations but also its quality and, therefore, its efficiency.

Figure 11. Percentage proportion of heartwood and sapwood in the stems of Scots pine trees (Pinus sylvestris L.) developed in conditions of former farmlands and forest soils in the mixed fresh coniferous forest site type

a)
I Kraft class (pre-dominant)
    b)
II Kraft class (dominant)

c)
III Kraft class (co-dominant)
Point of intersection of curves of the proportion of sapwood and heartwood (forest)
Point of intersection of curves of the proportion of sapwood and heartwood (farmlands)

DISCUSSION

The problem undertaken in this study seems to be important not only because of its cognitive value but, equally importantly, because of its practical connotations.

A number of literature items on the subject describe the proportion, primarily volume proportion, of sapwood and heartwood in tree trunks. [6, 12, 13, 14, 15]. Apart from the proportion itself in the stem volume, another important element which provides good quality appreciation of the timber raw material is the radial variability of heartwood and sapwood along the vertical axis of the stem.

It is only during the analysis which takes into account both volume as well as radial and axial variability in the proportion of heartwood that we can try to find factors influencing irregularities in the development of this zone and elaborate the model of the process of heartwood formation in the trunks of trees growing in different conditions.

The available literature also fails to suggest the possible origin of the stimulus and the impact of factors on the vertical formation of heartwood in pine tree trunks.

Berthier et al. [1] claim that the vertical heartwood distribution depends on the tree height. However, in view of the obtained results, it is rather difficult to agree with the above fairly general opinion because they point to the existence of other than the height stimuli which are difficult to verify but which appear to affect the vertical range of heartwood. It is quite likely that, similarly to the radial share of the sapwood, also here the tree crown, or more precisely its vitality, exerts a significant influence here. Moreover, the impact of genotypic factors in vertical formation of heartwood cannot be ruled out.

A considerable heartwood proportion in the large-sized timber raw material in pine trees derived from the former farmlands might indicate the possibility of its wider application in construction but as shown by Jelonek et al. [8], the strength of the heartwood from pine trees derived from farmlands is lower than from trees growing on typical forest soils. The above-mentioned researchers seek the causes of this situation in changes on the level of cell walls. Hence, caution should be applied when trying to optimise pine timber raw material derived from trees from former farmlands.

The observed greater proportion of heartwood in trees developed in conditions of farmlands can be attributed to a more dynamic process of aging of the wood tissue and dying of parenchyma cells which could probably be attributed to the crown size (volume surface area) which, in the case of pine trees developed in conditions of former farmlands on mixed fresh coniferous forest, was characterised by the smallest mean parameters (Tab. 2). Perhaps, blockages are formed in the xylem (softwood) of trees derived from farmlands resulting in the breakage of the column of water and the loss of water in the conducting elements causes the death of parenchyma cells and the formation of heartwood. Furthermore, it can be presumed that there must be a correlation between the assimilation apparatus, its size or efficiency and the development of blockages which, in turn, affects heartwood formation.

It can further be speculated that pine trees derived from the former farmlands which developed in conditions of mixed fresh coniferous forest, in the result of more intensive aging processes of the wood tissue [8] and low crown production efficiency, limit their conducting area (sapwood) by a more dynamic development of heartwood (Pipe Model Theory) [18, 19]. This allows the tree to maintain balance between the conducting zone (sapwood) and the assimilation surface.

The observed differences in the proportions of both of the examined wood zones in pine stems indicate the need to diversify the application of timber raw material and its prices depending on its origin.

Greater proportions of sapwood found in pine trees derived from typical forest soils, in comparison with pines developed in conditions of the former farmlands, appear to weigh in favour of the utilisation of the timber raw material derived from forest soils mainly in plywood and cellulose-paper industries with the timber raw material from the former farmlands used for construction purposes and to build containers for the chemical industry.

Our better recognition of factors impacting the development of the two types of wood will help optimise the utilisation of the timber raw material or even shape its development in tree trunks by the selection of suitable ecotypes as well as the appropriate selection in the course of breeding work.

The authors realise that the performed investigations failed to provide answers to all questions associated with the examined problems and believe that further studies will be undertaken soon.

CONCLUSIONS

  1. Both in the case of pine tree derived from the former farmlands and from typical forest soils, a higher proportion of heartwood was found in trees from fresh coniferous forest and higher proportion of sapwood from pine trees developed on mixed fresh coniferous forest.

  2. Forest site type and conditions of the tree growth exert a significant influence on both the process and rate of heartwood formation in the stems of Scots pines.

  3. The highest (62.1%) radial proportion of sapwood was determined in pine trees which grew in conditions of typical forest soils on fresh coniferous forest, whereas the lowest share of this zone (53.4%) was recorded in pines which developed in conditions of the former farmlands on mixed fresh coniferous forest.

  4. Large-sized timber raw material obtained from the stems of model trees was characterised by a higher proportion of heartwood (up to 63.5%) and lower share of sapwood (from 36.5%).

  5. Medium-sized timber raw material was characterised by a high proportion of sapwood ranging from 82% of the width of the radius in pine trees which developed in conditions of the former farmlands on mixed fresh coniferous forest to nearly 95% of the radial width in the remaining model trees.

  6. High determination coefficients R2 were obtained characterising interrelationships between the mean sapwood zone and crown volume (0.86) and the crown surface area (0.87) which may indicate a significant impact of the crown on the development of the width and area of sapwood in tree trunks.

  7. The authors found radial and axial variability of the heartwood formation process as well as of the proportion of both wood zones in tree trunks of Scots pines developed in conditions of the former farmlands and forest soils on fresh coniferous forest and mixed fresh coniferous forest sites against the background of biosocial classes.

  8. The significant proportion of sapwood found in the medium-sized timber raw material in pine trees developed on mixed fresh coniferous forest in conditions of typical forest soils can probably contribute to its higher efficiency during processing for cellulose-paper purposes.

  9. It can be assumed that the tree crown can influence the rate and the regularity of the course of the heartwood formation process in pine tree stems. Because of the complexity of the investigated problem, it is necessary to continue investigations.


REFERENCES

  1. Berthier S., Kokutse A., Stokes A., Fourcaud T. 2001. Irregular Heartwood Formation in Maritime Pine (Pinus pinaster Ait): Consequences for Biomechanical and Hydraulic Tree Functioning, Annals of Botany, vol.87, p.19-25, France.

  2. Duda J., Pazdrowski W. 1975. Procentowy udział twardzieli i bielu w 100-letnich sosnach zwyczajnych (Pinus sylvestris L.) rosnacych w różnych warunkach siedliskowych [Percentage proportion of heartwood and sapwood in 100-year old Scots pine trees] Sylwan nr 11, s. 57-64 [in Polish].

  3. Dudek A. 1969. Zależnosc intensywnosci przyrostu miaższosci i przyrostu piersnicy od wielkosci korony [Dependence of the intensity of volume and breast height diameter increments on the crown size ] Folia Forestalia Polonica, seria A, zeszyt 15, s.149-169 [in Polish].

  4. Dziewanowski R. 1967. Zarys rejonizacji jakosciowej sosnowego drewna tartacznego w Polsce [An outline of the quality regionalisation of pine saw timber in Poland] Prace ITD, nr 4 [In Polish].

  5. Grochowski J. 1973. Dendrometria [Dendrometry] PWRiL Warszawa [in Polish].

  6. Jakubowski M. 2004; Udział bielu, twardzieli, drewna młodocianego i dojrzałego w strzałach sosen zwyczajnych (Pinus sylvestris L.) wyrosłych w różnych warunkach siedliskowych [Proportion of sapwood, heartwood, juvenile and mature wood in trunks of Scots pines (Pinus sylvestris L.) developed in different site conditions] Sylwan nr 8, s. 16-24 [in Polish].

  7. Jelonek T., Pazdrowski W. 2004. Correlation between breast height diameter of trees, their crown biometric elements and selected wood macrostructural traits of scots pine (Pinus sylvestris l.), Annals of Warsaw Agricultural University, Forestry and Wood Technology, No 55, s. 263-267.

  8. Jelonek T., Pazdrowski W., Tomczak A. 2005. Share of sapwood and heartwood in stems of Scots pine trees (Pinus sylvestris l.) growing on forest soils and former farmlands as a basis for the evaluation of timber raw material, Annals of Warsaw Agricultural University, Forest and Wood Technology No 56, 2005.

  9. Krzysik F. 1978. Nauka o drewnie [Wood science] Wydawnictwo naukowe PWN, Warszawa [in Polish].

  10. Mućk H. 1984a. Drewno sosnowe i jego wykorzystanie [Pine wood and its utilisation] Las Polski, nr 4, s. 22-24 [in Polish].

  11. Mućk H., 1984b. Drewno sosnowe i jego wykorzystanie [Pine wood and its utilisation] Las Polski, nr 3, s. 17-21 [in Polish].

  12. Pazdrowski W. 1988. Wartosc techniczna drewna sosny zwyczajnej (Pinus sylvestris L.) w zależnosci od jakosci pni drzew w drzewostanach rębnych [Technical value of Scots pine (Pinus sylvestris L.) wood in relation to the quality of tree trunks in felling stands] Rocznik Akademii Rolniczej w Poznaniu, Rozprawy Naukowe, zeszyt 170 [in Polish].

  13. Pazdrowski W. 1992. Zwiazek pomiędzy udziałem bielu i twardzieli w miaższosci kłód odziomkowych sosen a udziałem obu rodzajów drewna w powierzchni przekroju poprzecznego pnia w miejscu scięcia i piersnicy drzew [Relation between the Share of Sapwood and Heartwood In the Volume of Pine Butt Logs and Share of Both Kind of Wood In the Cross-section of Stem At the Level of Felling and At the Breast Height of Teres] Sylwan, nr 7, s. 51-60 [in Polish].

  14. Pazdrowski W., Spława-Neyman S. 1996a. Budowa i fizyczna charakterystyka drewna sosny zwyczajnej (Pinus sylvestris L.) z drzewostanów w wieku przedrębnym, jako podstawa racjonalizacji przeznaczeń i wykorzystania surowca drzewnego [Structure and physical characteristics of Scots pine (Pinus sylvestris L.) wood derived from stands in their pre-felling age as the basis for the rationalisation of the final destination and utilisation of timber raw material] 10 Knferencja Naukowa Wydziału Technologii Drewna SGGW Warszawa [in Polish].

  15. Pazdrowski W. Spława-Neyman S. 1996b. Macrostructure of Scots pine wood from unripe forest stands grown in conditions of dry forest, Folia Forestalia Polonica, seria B, zeszyt 27, s.57-61.

  16. Praca zbiorowa; Ministerstwo Srodowiska 2003. Krajowy Program Zwiększania Lesistosci [State Program of Increasing Forest Area] Opracowanie zostało wykonane na podstawie pracy badawczej pt. “Modyfikacja krajowego programu zwiększania lesistosci. wykonanej w latach 2000-2002” przez IBL (główni autorzy:dr inż. Ryszard Kwiecień i doc. dr hab. Stanisław Zajac) [in Polish].

  17. Rynek Drzewny 2005. Przemysł drzewny-szacunkowe wyniki 2004 i prognozy na 2005 [Timber industry – estimation results for 2004 and prognostication for 2005] rok, nr II, s. 16 [in Polish].

  18. Shinozaki K., Yoda K., Hozumi K., Kira T. 1964a. A quantitative analysis of plant form - The pipe model theory, Basic analyses, Japans Journal of Ecology, vol.14, p.97-105.

  19. Shinozaki K., Yoda K., Hozumi K., Kira T. 1964b. A quantitative analysis of plant form - The pipe model theory, Further evidence of the theory and its application in forest ecology, Japans Journal of Ecology, vol.14, p.133-139.

  20. Stoces A., Berthier S. 2000. Irregular heartwood formation In Pinus pilaster Ait. Is related to eccentric, radial, stem growth, Forest Ecology and Management, France.

  21. Strona internetowa lasów państwowych 2006. [Internet page of State Forests 2006] http://www.lp.gov.pl/drewno/rynek_drzewny/rok2006/ilg_lisc_2006

  22. Strona internetowa lasów państwowych 2006. [Internet page of State Forests 2006] http://www.lasypanstwowe.gov.pl/mapy/index.htm.

  23. Zimmermann M. H., Brown C. L. 1981. Drzewa struktura i funkcje [Tree structure and functions] PWN, Warszawa [in Polish].

Scientific paper financed from financial resources intended for scientific research in years 2005-2006 as a research project No. 2 P06L 047 28 entitled: Macrostructural traits of Scots pine (Pinus sylvestris L.) timber developed on former farmlands and forest soils as the basis for the quality evaluation of timber raw material.

Accepted for print: 27.06.2006


Tomasz Jelonek
Department of Forest Utilization,
University of Life Sciences in Poznań, Poland
Wojska Polskiego 71 A, 60-625 Poznań, Poland
Phone: (+48 61) 8487754
email: tjelonek@au.poznan.pl

Witold Pazdrowski
Department of Forest Utilization,
University of Life Sciences in Poznań, Poland
Wojska Polskiego 71 A, 60-625 Poznań, Poland
Phone: (+48 61) 8487757
email: kul@au.poznan.pl

Arkadiusz Tomczak
Department of Forest Utilization,
University of Life Sciences in Poznań, Poland
Wojska Polskiego 71 A, 60-625 Poznań, Poland
Phone: (+48 61) 8487754
email: atomczak@au.poznan.pl

Ireneusz Stypuła
Białogard Forest Division,
Szczecinek Regional Directorate of State Forests RDSF, Poland

email: iron-pl@wp.pl

Responses to this article, comments are invited and should be submitted within three months of the publication of the article. If accepted for publication, they will be published in the chapter headed 'Discussions' and hyperlinked to the article.