1 Introduction.- 1.1 Prehistoric and Ancient Use.- 1.2 Changing Uses of Forests.- 2 Definitions and Descriptions.- 2.1 Introduction.- 2.2 Sapwood.- 2.2.1 Definitions.- 2.2.1.1 Sapwood.- 2.2.1.2 Included Sapwood.- 2.2.2 Area of Sapwood in Log Cross-Sections.- 2.2.3 Variation of Area of Sapwood.- 2.2.3.1 In a Species.- 2.2.3.2 In Different Species.- 2.2.3.3 Due to Age of Tree.- 2.2.3.4 Due to Rate of Growth.- 2.2.3.5 Due to Environment.- 2.2.4 Sapwood Contents.- 2.2.5 Discolored Sapwood.- 2.3 Intermediate Wood.- 2.3.1 Description.- 2.3.2 Occurrence.- 2.4 Transition Zone.- 2.4.1 Definition.- 2.4.2 Description.- 2.4.3 Occurrence.- 2.4.3.1 Heartwood Boundary Stain.- 2.5 Heartwood.- 2.5.1 Definition.- 2.5.2 Description.- 2.5.2.1 Appearance.- 2.5.2.2 Level of Maximum Area.- 2.5.2.3 Regular Heartwoods.- 2.5.2.4 Irregular Heartwoods.- 2.5.2.5 Variations in Appearance.- 2.6 Tree Exudates and Extracellular Materials.- 2.6.1 Definitions.- 2.6.1.1 Intercellular Secretory Spaces, Cavities, and Shakes.- 2.6.1.2 Intercellular Canals.- 2.6.1.3 Pitch Tubules and Stones.- 2.6.1.4 Pockets, Veins, and Streaks.- 2.6.2 Types of Exudate or Deposit.- 2.6.2.1 Resin.- 2.6.2.2 Gum.- 2.6.2.3 Kino.- 2.6.2.4 Latex.- 2.6.2.5 Manna.- 2.6.2.6 Amber.- 2.6.2.7 Balsam.- 2.6.2.8 Maple Sugar.- 2.6.2.9 Crystalline Compounds.- 2.6.3 Rate of Formation.- 3 Historical Aspects.- 3.1 The Use of Durable Woods.- 3.2 Exudates.- 3.3 Varnishes and Lacquers.- 3.4 Gums.- 3.5 Tannins.- 3.6 Dyes.- 3.7 Perfumes.- 3.8 Rubber.- 3.9 Medicines.- 3.10 Lessons from History.- 4 Influence of Forestry Aspects.- 4.1 Variation of Heartwood Volume.- 4.1.1 Heritability.- 4.1.2 Effect of Growth Rate and Crown Size.- 4.1.3 Influence of Environment.- 4.1.4 Influence of Injury and Health.- 4.2 Formation of Exudates.- 4.2.1 From Bark and Wood.- 4.2.2 From Wood.- 4.2.3 Addition of Stimulants.- 5 Chemical Features.- 5.1 Water and Gases.- 5.2 Inorganic Compounds.- 5.3 Storage Substances and Intermediates.- 5.4 Nitrogenous Compounds.- 5.5 Ethylene.- 5.6 Type of Extractives.- 5.6.1 Galactans and Cyclitols.- 5.6.2 Terpenoids.- 5.6.3 Fatty Acids and Related Compounds.- 5.6.4 Phenolic Compounds.- 5.6.4.1 Simple Phenols and Phenolic Acids.- 5.6.4.2 Lignans.- 5.6.4.3 Stilbenoids.- 5.6.4.4 Flavonoids.- 5.6.4.5 Quinones.- 5.6.4.6 Polymerized Polyphenols.- 5.6.4.7 In Different Tissues.- 5.7 Amount of Extractives.- 5.7.1 Position of Sample in the Tree.- 5.7.2 Effects of Rate of Growth 1ll.- 5.7.3 Effect of Site.- 5.7.4 Genetic Differences.- 5.7.5 Crystals.- 5.8 Reagents for Heartwood Detection.- 5.9 Exudates.- 5.9.1 Resin.- 5.9.2 Gum.- 5.9.3 Kino.- 5.9.4 Latex.- 5.9.5 Manna.- 6 Biological Features.- 6.1 Sapwood.- 6.1.1 Wood Tissues.- 6.1.2 Lumen Volume.- 6.1.3 Deposition of Extractives on Wall Surfaces.- 6.1.4 Impregnation of Cell Walls.- 6.1.5 Parenchyma.- 6.1.5.1 Volume.- 6.1.5.2 Cell Wall.- 6.1.5.3 Cytology.- 6.1.6 Respiration and Enzymes Activity.- 6.2 Transition Zone.- 6.2.1 Seasonal Variations.- 6.2.2 Appearance.- 6.2.3 Water Content.- 6.2.4 Pit Aspiration and Tylosis Formation.- 6.2.5 Cytology of Parenchyma Cells.- 6.2.6 Respiration.- 6.2.7 Enzyme Activity.- 6.2.8 Formation of Extractives.- 6.3 Heartwood.- 6.3.1 Seasonal Formation.- 6.3.2 Appearance.- 6.3.3 Respiration and Enzyme Activity.- 6.3.4 Location of Extractives.- 6.4 Wound Wood and Chemically Affected Wood.- 6.4.1 Wound Wood.- 6.4.2 Paraquat-Treated Woods.- 6.4.2.1 Biochemical Changes Due to Paraquat.- 6.4.3 Ethylene-Treated Wood.- 6.4.4 Knots.- 6.5 Exudates.- 6.5.1 General.- 6.5.2 Resin Formation.- 6.5.2.1 Anatomy of Pockets.- 6.5.3 Gum Formation.- 6.5.4 Kino Formation.- 6.5.4.1 Anatomy of Veins and Pockets.- 6.5.4.2 Chemistry of Kino Formation.- 6.5.5 Rubber Tapping.- 7 Function, Formation, and Control of Heartwood and Extractives.- 7.1 Function and Volume of Sapwood.- 7.1.1 Function.- 7.1.2 Volume.- 7.2 Types and Formation of Heartwood.- 7.2.1 Introduction.- 7.2.2 Types of Heartwood.- 7.2.2.1 Regular Heartwoods.- 7.2.2.2 Other Types.- 7.2.3 Conclusions.- 7.3 Features of Heartwood and Woundwood.- 7.3.1 Some Theories of Heartwood Formation.- 7.3.1.1 Natural Causes.- 7.3.1.2 Accumulation of Gas and Control of Water Content.- 7.3.1.3 Initiation by Fungi and Hormones.- 7.3.2 Anatomical Changes.- 7.3.3 Occurrence of Extractives.- 7.4 The Transition Zone and its Formation.- 7.5 Function of Extractives and Exudates.- 7.6 Formation of Exudates and Extractives.- 7.6.1 Differences in Composition.- 7.6.2 Site of Formation.- 7.6.2.1 Exudates.- 7.6.2.2 Extractives.- 7.6.3 Amounts.- 7.6.4 Type of Extractives in Tissues.- 7.7 Initiation of Formation of Heartwood, Extractives, and Exudates.- 7.7.1 Initiation by Displacement of Water.- 7.7.2 Initiation by Changes in Ethylene Levels and in Hormonal Balance.- 7.8 Factors Controlling the Nature of Extractives and Exudates.- 7.9 Activities at Cellular Levels.- 7.10 Conclusions.- References.

Heartwood and Tree Exudates

Form and function of arabinogalactans and arabinogalactan-proteins

This paper reviews recent literature on the formation of heartwood and on the components that affect natural durability It includes discussion about the function of heartwood in living trees, factors influencing the natural durability of heartwood, the process of heartwood formation, and variations in heartwood quantity and quality Heartwood formation is a regular occurrence in tree stems, and heartwood may have many different properties from sapwood, including natural decay resistance A greater understanding of the heartwood formation process could allow control of heartwood production Recent research involving enzymatic analyses have provided valuable insight into the biochemical processes involved in heartwood formation Further study of the role natural durability plays in living trees would help to bring together many of the disparate strands of research relating to heartwood

/pdf/heartwood-formation-and-natural-durability-a-review-dy7pxi7px2.pdf

Heartwood formation and natural durability - a review

Publisher Summary This chapter provides an overview on the main groups of plant polysaccharide other than those, such as starch and fructans. Plant polysaccharides fall into a number of well-defined structural families. The availability of modern techniques has made possible the development of a new and powerful complementary approach to the study of plant cell polysaccharides. Biologically homogeneous primary cell walls are readily obtained from undifferentiated cells grown in suspension culture. The methylation technique is then applied to the total mixture of polysaccharides present in the cell wall and to fractions derived there from by the use of purified hydrolytic enzymes. In addition to cellulose, two other β-D-glucans are of widespread although not abundant occurrence in plants, namely, those containing 1–3 linkages only and those containing both 1–3 and 1–4 linkages. In contrast to cellulose and callose, the mixed glucans are generally rather soluble in aqueous solvents. Some β -D-glucans are only isolated by extraction with alkali, and evidence shows that these glucans are cell wall components and are probably covalently linked to other macro-molecules.

Chemistry of Cell Wall Polysaccharides

Larch heartwood is appreciated for its good mechanical properties, its colour and its texture, and it is often used outdoors because of its natural durability (decay resistance). In this study the colour of larch heartwood was studied in relation to extractives and decay resistance, with the aim to estimate durability of larch heartwood from its colour. On a total of 293 trees colour in the CIE L*a*b* space (L* lightness, a* red/green axis, b* yellow/blue axis), extractives content (acetone and hot-water extractives, amount of phenolics) and the brown-rot decay resistance were determined. For calculating the relative decay resistance ( x), mass loss after inoculation for 16 weeks with two fungi [ Coniophora puteana (Schum.ex.Fr.) Karst., Poria placenta (Fr.) Cke, European standard EN 113] of larch heartwood samples was compared to Scots pine ( Pinus sylvestris L) sapwood reference samples (EN 350-1). Different species [Japanese larch ( Larix kaempferi Lamb.), Hybrid larch (Larix deciduax L. kaempferi) and European larch ( L. decidua Mill.)], provenances and age classes (38-year, >150-year) were included. Japanese larch heartwood turned out to be significantly more reddish (higher a*-values) compared to the European larch provenances. Reddishness of the hybrids was intermediate. The red hue (+a*) was strongly correlated with the amount of phenols ( r =0.84) and decay resistance ( r =0.63) and therefore suitable for prediction of both parameters. The results suggest that colour measurements of larch heartwood could be of benefit in tree breeding programs and for an optimised utilization of larch timber.

Colour of larch heartwood and relationships to extractives and brown-rot decay resistance.

Studies on Larch Arabinogalactan. I. The Distribution of Arabinogalactan in Larch Wood

https://www.degruyter.com/view/j/hfsg.1967.21.issue-3/hfsg.1967.21.3.85/hfsg.1967.21.3.85.pdf

B. W. Simson

Papers

Studies on Larch Arabinogalactan. I. The Distribution of Arabinogalactan in Larch Wood

Studies on Larch Arabinogalactan. II. Degradation of Arabinogalactan within the Living Tree