TREE DECAY AN EXPANDED CONCEPT
TREE DECAY AN EXPANDED CONCEPT
As time
passes, fewer species of organisms survive on the wound surface. The concentration of anyone group of
organisms on the wound surface may fluctuate greatly if there are temperature
extremes in the seasons. But now most of
the action is inside the tree. A look into
the tree after a year shows that a few microorganisms surmounted the chemical
barriers formed by the tree. The
microorganisms either used the protective materials in the barrier as nutrients
or altered these materials in such a way that they were no longer toxic. The protective materials are mostly phenolic
compounds in angiosperms and terpenes in gymnosperms. Oxidation and polymerization of these
materials take place after wounding.
Usually, but definitely not always, the microorganisms that are the
first to infect are bacteria and nondecay fungi. In some cases, decay-causing fungi are
first. The microorganisms that are the
first to infect are called PIONEERS.
Which microorganisms become the pioneers is affected greatly by many
factors-time of year of wounding; type, position, and severity of wound. The pioneers in turn affect greatly the
species of microorganisms that follow in the succession. And, the species that follow will affect
greatly the rate and type of wood alteration.
Successions are orderly, but complex. (fig. 12)
隨著時間的進行，少數種類微生物在樹作傷口存活，在樹木傷口表面，大多微生物可能在季節極端的溫度變化，族群會有大幅度的波動。
但是大部分的活動是在樹內，有一些微生物可以在一年後，突破樹木形成的化學屏障。它們可以改變保護樹木材料或作為營養來源，而不中毒。
被子樹木保護材料主要為芬類化合物，而裸子樹木為三帖類，這類物質在樹木受傷後，產生氧化和聚合反應。
通常第一個感染樹木微生物是細菌和非腐朽真菌，但在某些情況下，樹木腐朽真菌是第一個感染。
第一個感染的微生物為先驅者。依樹木受傷的嚴重性、類型與位置，先驅微生物的種類而有所不同，先驅者的種類會影響之後微生物的演替，樹木腐朽速率和類型。演替是有序而復雜的。
MICROORGANISMS:
1) Bacteria,
2) Cytospora, 3) Pyrenochaeta,
4)Phoma, 5) Phialophora,
6) Gliocladium,
7) Graphium, 8) Cephalosporium,
9) Coniothyrium,
10) Fusarium, 11) Rhinocladiella,
12) Acrostaphalus,
13) Trichocladium,
14) Yeasts.
1) Bacteria,
2) Cytospora, 3) Pyrenochaeta,
4)Phoma, 5) Phialophora,
6) Gliocladium,
7) Graphium, 8) Cephalosporium,
9) Coniothyrium,
10) Fusarium, 11) Rhinocladiella,
12) Acrostaphalus,
13) Trichocladium,
14) Yeasts.
資料來源:
Alex L. Shigo
Plant Pathologist,
U.S. Department of Agriculture, Forest Service, Northeastern Forest Experiment
Station, Durham New Hampshire
Agriculture
Information Bulletin Number 419 April 1979
翻譯:樹沃客樹藝
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