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Wood ()

Mount Usu / Sarobetsu post-mined peatland
From left: Crater basin in 1986 and 2006. Cottongrass / Daylily

[ wood physics | wood chemistry | forest science | tree ]

the secondary xylem in the stems of trees (s.s.)
the secondary xylem and the same type of tissue elsewhere such as in the roots of trees or shrubs (s.l.)

Wood physics (木材物理)

The area of wood science concerned with the physical and mechanical properties of wood and the factors which affect them.

Wood density (材密度)

= wood specific gravity
= the dry weight per unit volume of wood

specific gravity = oven dry weight/fresh volume
water content = (wet weight - dry weight)/fresh volume

using in allometric equations estimating tree biomass and carbon stocks from stem diameters
indicating fire tolerance

The heaviest wood density is reported from Krugiodendron ferreum (black ironwood) of which density is 1.3 g/cm³ → sinking

Table. Representative wood densities (as a guide). The density is fluctuated due to location, water content, part, etc. -: not determined.
Species = Wood density (g/cm³)
Abies sachalinensis (トドマツ) = 0.42
maples (Acer amoenum (オオモミジ), A. japonicum (ハウチワカエデ), A. mono (エゾイタヤ), A. negundo (ネグンドカエデ) ≈ 0.67
Betula platyphylla (シラカンバ) = 0.64
Castanea crenata (クリ) = 0.60-0.68
Cercidiphyllum japonicum (カツラ) = 0.45
Ginkgo biloba (イチョウ) = 0.55
Picea jezoensis (キハダ) = 0.45
Picea jezoensis (エゾマツ) = 0.48
Pinus nigra (オウシュウクロマツ) = 0.48
Populus nigra (セイヨウハコヤナギ / ポプラ) = 0.45
Prunus sargentii (エゾヤマザクラ) = 0.63
Quercus mongolica (ミズナラ) = 0.68
Quercus rubra (アカナラ) = 0.54
Robinia pseudoacacia (ニセアカシア) = 0.75
Sorbus commixta (ナナカマド) = 0.71
Taxus cuspidata (イチイ) = 0.48
Tilia japonica (シナノキ) = 0.44
Tilia maximowicziana (オオバボダイジュ) = 0.43
Ulmus davidiana (ハルニレ) = 0.59
The table is used for estimating CO2 fixing in trees in a field trip, Nature in the eco-campus of Hokkaido Universit (北大エコキャンパスの自然)
Table 1. Comparison of lowland forests in number of tree species, mean of specific gravity per forest and mean of the standard deviation (SD) of specific gravity per forest in the three regions. n = number of samples (Williamson 1989)
  Forest type and location  n  Mean species  Specific gravity
                               richness      Mean  SD

  Indiana (temperate)
    Beach-maple             15   19.2        0.53  0.08
    Mixed woods              5   20.2        0.53  0.09
    Oak-hickory              3   17.7        0.53  0.09
    Lowland depression       7   23.0        0.53  0.08
  Costa Rica (tropical)
    Tropical dry             1   90          0.53  0.20
    Tropical moist           2  114          0.50  0.14
    Tropical wet             2  149          0.48  0.16
    Deciduous seasonal       2   55          0.58  0.17
    Semi-evergreen seasonal  5   60          0.59  0.17
    Evergreen seasonal       6   93          0.58  0.18

Fig. Specific gravity as a function of distance from pith
for Ceiba pentandra from a tropical dry forest and a tropical
wet forest.

tree ring analysis (年輪解析)

Standardization (標準化)
1. general standardization (一般的標準化)
2. removing growth trend (成長傾向除去)
3. conceptual linear aggregate model (for tree-rings)

Rt = At + Ct + D1t + D2t + Et

Rt = the measured tree-ring series
At = the age-size-related growth trend
Ct = the recorded climate signal
D1t = the disturbance pulse caused by local disturbance
D2t = the disturbance pulse caused by standwide disturbance
Et = everything else that is or is not measurable but still contributes to tree-ring growth

4. spline (スプライン)

Dendrochronology (年輪年代学)

= tree-ring dating ⇒ dendroclimatology
Table 1 Subfield of dendrochronology (Speer 2012).
Dendroarchaeology (年輪考古学)
Tree-ring samples from beams and posts in archaeological dwellings are dated to provide construction dates for the dwellings. The position of these beams in the dwelling can be used to study the timing of construction and expansion of dwellings and to start to understand human behavior in these cultures. Correlation with regional master chronologies can also help to dendro-provenance archaeological and historical wood object.

[ climatology ]

Dendroclimatology (年輪気候学)
Because trees are an important functional feature of many ecosystems, they can be used as a natural record of ecological processes, such as tree-line movement, successional processes through the establishment and death of trees, fire occurrence (Dendropyrochronology), insect outbreaks, (Dendroentomology), synchronous fruiting (masting) in trees (Dendromastecology), or movement of invasive tree species.

[ geography ]

Dendrogeomorphology (年輪地形学)
The vertical structure of a tree enables it to gather the most light while standing up straight so that land movement can be reconstructed by the tilting of a tree and the resultant reaction wood (thicker growth rings produced to straighten the stem of a tree). Also tree death or establishment can be used to date geologic phenomena such as landslides, mudflows, seismic activity along faults (Dendroseismology), glacial activity (Dendroglaciology), or volcanic events (Dendrovolcanology).

[ chemistry ]

Dendrochemistry (年輪化学)
Trees absorb chemicals along with the water that they absorb from soil and the gases that they take in from the atmosphere. These chemicals are deposited in the wood in the trees’ stem, roots, and branches and can be used as a record of contamination, nutrient availability, and pollution. Stable isotopes can also be measured in wood structure to reconstruct past temperature, humidity, and the source of water or growing conditions of the trees.

Wood processing (木材加工)

= log processing, timber processing
_├──────────────── xylem ───────────────┼ phloem
_______└ earlywood ─┘┬└annual ring_____________┬ └ bark ┘
_pith__○ resin duct__latewood__________false ring__cambium
Fig. Pine crosssection. Conifer trees in temperate areas produce one ring per year. These rings can be broken into the earlywood portion (open cells with thin cell walls) and the latewood portion (cells with thick cell walls and a smaller lumen). Other features that are present are the pith, resin ducts, cambium, and the bark. The variation in ring width is generally driven by climate and results in the pattern of wide and narrow rings that we use to cross date the wood samples. Sometimes a false ring may be present, as in this sample, where the tree growth slows because of a reduction in the limiting factor for growth of the tree, such as drought. When that environmental factor limiting growth returns (e.g. when it rains), the tree resumes growth and the cells grade back to earlywood structure with thinner cell walls.

Classification of wood based on vessel arrangement

diffuse-porous wood_ ring-porous wood___radial-porous wood
(○ : vessel)

Ring-porous wood (環孔材): with the earlywood pores clearly forming rings or bands

Ulmus davidiana

Quercus mongolica_____________Phellodendron amurense
Semi-ring-porous wood: pores do not form clear rows with gradual decrease in size from the earlywood to the latewood

Diffuse-porous wood (散孔材): with no clear earlywood-latewood pore arrangement

Ex. Magnolia obovata, Betula platyphylla, Acer mono, Aesculus turbinata

Radial-porous wood (放射孔材)

Wood tissue

Betula platyphylla
Alnus hirsta_____Betula ermanii__Betula platyphylla_Taxus cuspidatum

[analytical chemistry (分析化学), cell wall(細胞壁)]

Wood chemistry (木材化学)

Focusing on the chemical and biochemical aspects of trees and products such as pulp and paper that are derived from trees
Three major components

Cellulose (セルロース)

The major component of trees → more than 50% of wood (or woody part) for broad-leaved and needle-leaved trees are cellulose

Role (in a metaphorical sense): wood = ferroconcrete ⇔ cellulose = rebar

1973 Albersheim: cambium of sycamore (Acer pseudoplatanus)

cultured cell - observed cell wall
isolated polysaccharides from extracted SEPS(sycamore extracellular polysaccharide) by a sucrose density-gradient centrifugation method
1. a neutral fraction contained xyloglucan
2. a weakly acidic fraction contained arabinogluctan
3. a strongly acidic fraction contained rhamnoglacturonan
Based on these results, he established Aebushein's cell wall model (細胞壁モデル)

Hemicellulose (ヘミセルロース)

Ex. Cell wall of Avena sativa L.
Glu____________Gal__Man Ava_Xyl_uromic acid, etc.
Hemicellulose A__28___11__1__18__26_____16
Hemicellulose B__26____6__1__22__29_____16

Lignin (リグニン)

(Broad-leaved tree: 20-25%) < (Needle-leaved tree: 28-31%)
Basic unit: phenylpropane-typed (C6-C3) carbon skeleton
→ different structural components between species

needle-leaved tree: guaiacylpropane (グワヤシルプロパン)
borad-leaved tree: syringylpropane (シリンギルプロパン)
babmoo and dwarf bamboo: condensation product of guaiacylpropane, syringylpropaneand p-hydroxyphenylpropane (p-ヒドロキシフェニルプロパン)