FRST 210 lesson 7- Heartwood and the great longevity of trees

Why do bristlecone pines live for so long?

• They are less susceptible to organisms that weaken and cause death of trees, particularly fungi and insects

• Grow in an arid cold climate at high elevations which does not favor wood destroying organisms

• Heartwood of Bristlecone pine is vey resinous and repellent t to wood destroying organisms

Functions of sapwood

• Mechanical support of the crown

• Conduction of fluids from the soil to the leaves

• Storage of photosynthetic products such as starch and simple sugars, storage of minerals

The last function is provided by living parencyham cells (both ray and longitudinal parenchyma)

The ortion of the tree stem contains living parenchyma and is physiologicall termed sapwood:

Fill in the blank: Text list: Outer bark, inner bark, Vascular Cambium, Sapwood, Heartwood, Sugar flow in phloem (inner bark), Water flow in sapwood

• Top arrow: outer bark

• Right below it: Inner bark

• Sugar flow in phloem (inner bark)

• Water flow in sapwood

• Vascular Cambium

• Sapwood

• Heartwood

How are heartwoods formed?

• When a tree reaches a certain age, which varies greatly between and within species, changes take place in wood that lead to the death of living parenchyma cells

• The tissue, which is not physiologically dead and does not conduct water lead to this.

Two functions of heartwood

• Serves as a repository (storage) for accumulated toxic products of metabolism, which enhance the durability of wood enabling the tree to resist fungal and insect attack

• A mechanism by which the tree maintains sapwood volume at the optimum level for water conduction and fod storage.

Which chemical component of wood has been used as an antibacterial agent in tooth paste?

• Extractives

Name a Canadian timber that is regarded as durable, i.e. will last 15 to 25 years in aground contact (grave-yard) test

• Western Red Cedar

Wood that is perishable (<5 years service)

• Sapwood of all species

Non-durable wood (5-10 years service)

• Hemlock, true firs, spruce jack pine, lodgepole ppine

Moderately Durable wood (10-15 years service)

• Larch, southerine Douglas-fir

Very Durable (>25 years service)

• Ipe (no Canadian species)

Extractives

• Components of wood that can be easily removed by a solvent including water

• Water or solvent soluble materials found in Wood

Why aresome wood considered to have natural durability

• In some wood species, their heartwood extractives are poisonous to fungi and insects

• These wood species possess natural durability

• ‘The inherent resistance of wood to biological degradation (mainly by fungi, insects, marine boring molluscs and crustaceans)

Two main functions for the formation of heartwood

• Repository (storage) for the accumulated toxic products of metabolism that enhance the durability of wood enabling the tree to resist fungal and insect attack

• Is a mechanisms that allows the tree to maintain sapwood volume at the optimum level for water conduction and food storage

Are resin canals always found in xylem and phloem tissues?

• No

Some extractives in Western Red Cedar

• Plicatic acid

• Plicatin

• a-thujaplicin

• B-thujaplicin

• y-tjujaplicin

Which specific wood extractives were sprayed onto logs to prevent fungal staining of sapwood?

• Western rec cedar extractives (thujaplicins)

• Thujaplicins are used in skin creams in Vancouver