Tuesday, September 15, 2009
From Little Acorns
From small to large is a general growth pattern of living organisms. As with the mustard seed*, so it is with the acorn. Both the mustard tree and the oak tree start their lives as germinated seeds which develop into saplings before becoming mature trees capable of reproducing themselves. In truth, the mustard tree is more like a shrub that grows to a height of about 2 metres, but both arboreal follow the same principle of growth, i.e., with age, they increase in size. Like other trees, they support and provide shelter for many species, but the gigantic oak surpasses most in this respect.
An oak tree can live up to 200 years, and exceptionally for 1,000 years, by which time its trunk may be 45 feet thick near the base. Being monoecious it produces male catkins that each contains several million pollen grains for dispersal by the wind for fertilizing thousands of inconspicuous female flowers via their receptive stigma. These fertilized flowers are transformed into acorns which ripen in the autumn ready for a new cycle of life to begin. A visiting Jay or Magpie could carry one such acorn a mile or more before burying it where the conditions may be right for germination.
The longevity and size of an oak tree provides a secure habitat for hundreds of organism and insects and therefore it has an important role within the immediate ecosystem. Many species rely on oak trees for their survival; one such creature is a wasp (Biorhiza pallida) that interacts with the tree to produce a gall in the form of an oak apple. Spangle galls are also induced on catkins and the undersides of leaves by asexual wasps, while communities of parasitic and predatory insects thrive on the tree. Moth larvae and caterpillars feed on the leaves and the Oak Bark Beetle burrows in the wood. Nut Weevils lay their eggs in the acorns and the larvae pupate when the acorns fall to the ground. Spiders take advantage of the supporting framework of leaves and twigs by spinning their webs between them, while other camouflaged arachnids wait hidden in bark crevices. In turn, birds such as the Chaffinch, Tree Creeper and the Wood Warbler feed on the insects.
Unfortunately, oak trees are not protected unless they are subject to a preservation order by a local Planning Department, but if an order is infringed the offender may be required to pay a penalty of up to £50,000 per tree or even time in jail. By right oak trees belong to the landowner who may do what they like with them.
Anon: “Mighty oaks from little acorns grow.”