Juvenile Wood in Juvenile Wood in Pines Pines

Overview

• Basics Of Wood Production

• What Is Juvenile Wood

• Characteristics

• What influences Juvenile Wood

• What Are The Problems With It

• How To Manage It

Basics of Wood Basics of Wood ProductionProduction

Tracheids

• Structure

• Functions– Water transport in the xylem– Support– Storage

Growth Rings

• Trees produce two types of rings during the a growing season

• Spring Wood (early wood)

• Summer Wood (late wood)

What is Juvenile What is Juvenile WoodWood

Where it is Found

• First set of growth rings extending out from the pith of the tree

When it is produced

• Is highly variable between species, stands, and individuals

• It is produced by all tree, but species and site location play a large part in determining its impact

• Can be between 3 to 20 years average of 10 years

CharacteristicsCharacteristics

Growth rings

• Wide growth rings

• Ring Age

• Uniformity

Tracheid characteristics– Wall thickness and tracheid diameter– Tracheid length– Angle

Growth rings

Specific Gravity– Less summer wood in Juvenile wood– Much lower specific gravity

Growth rings

Tracheid characteristics

What influences What influences Juvenile WoodJuvenile Wood

• Competition

• Live crown

• Growth rate

• Geographic location

ProblemProblem

• Strength

• Shrinkage

• Compression wood formation

Tanzania

• South African Forestry Journal – No. 172 March 1995 p 19-23

• Indigenous lumber sources were insufficient for the needs of the country

• Plantation of Pinus patula

• 60,000 ha planted

• 49% of stems consisted of Juvenile wood

How to manage for How to manage for Juvenile WoodJuvenile Wood

Stand density

• Initial spacing

• Spacing and thinning

Fertilization

• Increases foliar mass and photosynthetic ability

• Decrease in summer wood production and specific gravity

• Less pronounced in mature wood

• Promotes spring wood production

Irrigation

• Early application has same results as seen with fertilization

• Promotes spring wood production

• Late application prolongs cambial activity

• Promotes summer wood production

Removing Competing Vegetation

• Early removal promotes seedling growth

• Continued removal into the pole stage to reduce competition and increase growth, but promotes juvenile wood

• Juvenile wood produced for a longer period of time, but higher specific gravity

Summary

• Juvenile wood is in all trees, but can be a problem in rapid growing pine species

• It is influence by competition, live crown, growth rate and location

• It can be managed by controlling stand density, fertilization, irrigation, and managing competing vegetation