Quiz: Describe the difference in wood structure between diffuse porous and ring porous trees.



Meristem- key to tree growth,

Undifferentiated cells, located on surface area of tree, apical and lateral



Growth of individual tree parts


1. Branches (aka Shoots) and Leaves:



Growth: primordia located in buds, leaves grow out first and then shoot elongation. Elongation stimulated by auxins.



Indeterminate vs. determinate (free vs. fixed)

IND- can grow throughout growing season, multiple flushes; maples, birches, cherries

Determinate- only one set of leaves and shoots per season- oaks and pines


Early Leaves vs. Late leaves




2. Roots:





Growth similar to shoot growth (cells)- at apical meristem.

Correlation of elongation to root diameter. Elong. Also affected by temperature, excess water (because of oxygen losses), compaction



3.      Bole


Meristem divides into fusiform cells and ray cells ( both are in xylem),


Ring width and area:

Wood is produced along perimeter,

From base of crown downwards




Types of Wood:

Coniferous wood- tracheids, no differentiation in function (support or transport) of tracheids

Diffuse porous- small vessels spread throughout wood used for water transport

Ring porous- large vessels in early wood and smaller vessels in late wood

Diffuse vs. Ring Porous wood


Early vs. late wood


Diffuse vs. ring porous rings



Reaction Wood


Compression conifers, forms on underside



Tension- hardwoods, forms on the upperside





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