So after being in the cold, windy, rainy woods for about half an hour and then being presented with a blind fold it was safe to say we were not all so sure about the next activity. Not that I didn’t trust Catherine to lead me round Seeley Corpse with out making me fall down a hole- because I did, but being able to find my tree again by just feeling the bark… not as convincing. Not only did Catherine make me feel my tree she also made me hug and kiss it so that I could and I quote “fully know what the bark of my tree felt like!”
This hole activity made me not only question Catherine’s insanity but also why on earth do tree’s have bark? And if they all have bark, then why does each trees bark feel different?
It turns out that bark serves the same purpose to a tree as skin does to us- its an outer protective layer! Bark acts as a defence against herbivores, insects and parasitic plants. Just underneath the bark is a think layer called the cambium, this is the only part of the tree that is living and producing cells. The cambium causes the trunk, branches and roots grow thicker over time.
The reason that different trees have different bark is not only dependent on the specie of tree but also how they have evolved overtime for survival.
- Have very smooth bark which makes it hard for insects and ivy to gain a foothold.
- To keep the surface, smooth the beech tree grows very slowly.
- This means that its slow to seal injuries for example where a branch has snapped off.
- Has a very limited overall growth rate.
- The bark of an oak tree grows 4 times faster than the oak on beach trees!
- They can repair very quickly
- Their thick bark helps them to moisture- so that they can survive in a dry Mediterranean environment.
- Their rapid growth causes their bark wrinkle and crack harbouring insects.
- To prevent this, oak trees must use a big proportion of their metabolic resources producing tannins (a very acidic substance to deter insects).
Other trees in very damp environments such as Birch trees often have very thin bark that they shred regular. This is because they are prone to lichen and mass infection. Therefor exfoliating regularly like this, allows them to get rid of parasites.
So yes after hugging pretty much every tree in Seeley Corpse I was eventually reunited with my tree!References:
Parsons, P. (2010) Science 1001. London: Quercus Publishing
http://www.sciencefocous.com (accessed 1st March 2016)