Botany Photo of the Day

Third in a series featuring photographs and writings from other staff and researchers at UBC Botanical Garden and Centre for Plant Research. Today's photographs and comments are by Peter Wharton, Curator of the David C. Lam Asian Garden. – Daniel

View Part I here – NB: I mixed up the slide numbers so part I now has a different photograph!

... As generations pass, tree weight and windstorms increasingly cause individuals to assume prone positions, yet live on (today's photograph 1). These trees still thrive as their root systems remain undamaged, no doubt assisted by their renowned, flexible wood. If they fall across a ravine, their upper branchlets can take root on the opposite bank, thus the mother tree can in a sense move laterally! In many cases these prone “bridge trees” form vertical “stockades” of young growth along their upper trunks, from crown tip to root crown. This I have seen in the numerous gills or steep sided ravines that are a feature of this area. The final photograph (today's photo 2) shows a history of a mother tree, a falling event (or rooting lateral branch) and resumption of reiterative vertical growth. The vegetative propagative attributes of this species, on unstable bedrock, has helped sustain this tree in a region that is still too cool to allow reliable seedling regeneration. Our warming earth could of course change this situation rather soon.

The age of these specimens on Castle Hill Wood appear to range from 400 to 800 years, with a few no doubt approaching a 1000 years. Recent work in southern Britain is indicating that old coppiced specimens may live as long as several thousand years – competition for the English yew (Taxus baccata). It is gratifying to see the obvious improvements in ancient woodland conservation management in areas I knew as a boy. For instance, the retention of stumps, snags and fallen logs is the norm in British native woodlands.

Those wanting more information on veteran trees should investigate English Nature's Veteran Trees Management Handbook or The Future for Veteran Trees (PDF).

The extensive groundcover in the photos above is dog's mercury (Mercurialis perennis). This area is also home to a host of interesting British herbaceous natives, including ramsons (Allium ursinum), giant bellflower (Campanula latifolia), lady's slipper orchid (Cypripedium calceolus) – which my father saw on his honeymoon 56 years ago! –, daffodil (Narcissus pseudonarcissus) and Herb Paris (Paris quadrifolia).

Science resource link by Daniel: ScienceBlogs – “features blogs from a wide array of scientific disciplines... It is a global, digital science salon.”