Juvenile Wood in Pines

1
Juvenile Wood in Pines
2
Overview

• Basics Of Wood Production
• What Is Juvenile Wood
• Characteristics
• What influences Juvenile Wood
• What Are The Problems With It
• How To Manage It

3
Basics of Wood Production
4
Tracheids

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

5
Growth Rings

• Trees produce two types of rings during the a
  growing season
• Spring Wood (early wood)
• Summer Wood (late wood)

6
What is Juvenile Wood
7
Where it is Found

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

8
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

9
Characteristics
10
Growth rings

• Wide growth rings
• Ring Age
• Uniformity

11
Tracheid characteristics

• Growth rings

• Wall thickness and tracheid diameter
• Tracheid length
• Angle

12
Specific Gravity

• Growth rings

• Tracheid characteristics

• Less summer wood in Juvenile wood
• Much lower specific gravity

13
What influences Juvenile Wood
14

• Competition
• Live crown
• Growth rate
• Geographic location

15
Problem
16

• Strength
• Shrinkage
• Compression wood formation

17
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

18
How to manage for Juvenile Wood
19
Stand density

• Initial spacing
• Spacing and thinning

20
Fertilization

• Increases foliar mass and photosynthetic ability
• Decrease in summer wood production and specific
  gravity
• Less pronounced in mature wood
• Promotes spring wood production

21
Irrigation

• Early application has same results as seen with
  fertilization
• Promotes spring wood production
• Late application prolongs cambial activity
• Promotes summer wood production

22
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

23
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