How trees grow
The guide separates upward growth from outward thickening and then links both to the cambium and the root system.
Apical growth is the increase in height and extension at the buds. Radial growth is the thickening of trunk, branches, twigs, and roots.
Only a small portion of a tree is actually living tissue. The living growth layer lies beneath the bark in the cambium. The rest is mainly non-living woody structure.
Apical bud growth in three stages
- The bud at the tip opens
- The leaves emerge and enlarge
- The stem lengthens between the leaves
Looking closely at twigs can give clues about how much extension growth happened in previous years.
Roots are usually shallower than people think
The guide challenges the idea that roots mirror the crown. Most roots are close to the soil surface, with a strong spread of lateral roots rather than a deep mirror image underground.
Roots often extend beyond the canopy
Root spread is commonly underestimated. In some cases roots can extend at least as far as the tree is tall, and sometimes much farther.
Key takeaway
Tree growth is not just upward. A tree is always extending, thickening, and adjusting its root system at the same time.
Knowledge check
Do roots usually mirror the shape of the crown?