Blog - lignin

Woodland carbon recycling

Woodland carbon recycling

by Lewis, 9 November, 2012, 0 comments

The world store of terrestrial carbon is estimated at 2860Pg (petagram = 1015 g), of this, some 1240 Pg is ‘locked up’ in woodlands – that is over 40%. Much of woodland carbon is ‘locked’ in dead leaves and decaying wood – in the form of complex organic molecules (carbohydrates, proteins, lignin, cellulose, pectates etc) that make up a plant. However, with time these molecules can be degraded, broken down by the activities of micro-organisms (bacteria and fungi) – though the first stage of the process may be a physical disruption by beetles (saproxylic) and other burrowing small animals. The activity of fungi is more obvious / visible at this time of year (autumn) as their fruiting bodies Read more...

Woody tissues : bark

Woody tissues : bark

by Chris, 28 April, 2011, 2 comments

Wood is such a familiar material that we tend to take it for granted. In general, it is a long lasting, fibrous material that is found within the roots, stems and branches of trees and shrubs. It is mainly composed of xylem – a tissue that brings water and minerals up from the roots and distributes the minerals and water to the leaves and growing tissues of the stem. Read more...

Annual rings : counting the years ......

Annual rings : counting the years ……

by Chris, 10 March, 2011, 3 comments

Most trees and shrubs that grow in temperate regions, where there are clear alternations of seasons (cold – warm, or wet – dry) produce annual rings in their stems or roots. Annual rings come about because there is a difference in the “wood cells” (xylem : see below) formed when growth is fast, as in the Spring, or slow, as in late Autumn. This is in marked contrast to the trees or perennials of wet, tropical forests where the climate is more uniform, as is the wood formed. Read more...

Estimating the Age of a Tree - Counting the annual rings

Estimating the Age of a Tree – Counting the annual rings

by Angus, 9 May, 2008, 10 comments

When a tree has been cut down or felled, then it is relatively easy to work out its age by counting the growth or annual rings that can be seen on the sawn-off stump. Under the bark of a tree is a special tissue (called the cambium) which forms new cells so that the tree can grow. Differences in the rate at which cells are produced by this tissue give rise to the annual or growth rings. If conditions are good for growth (warm, regular rainfall) then the ring that is formed will be wider than that created in a year where the tree struggles for water, or it is cold. There is one ring for each year of a tree's life. (In any given year, an annual ring will have two components - a lighter coloured band of tissue (larger vessels) formed in the Spring and Summer and a darker band (smaller vessels)that is created when growth is slower in late Summer / Autumn.) Read more...

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