Bulletin Spring‧Summer 2005

SlopeGreening—ItsChallengesandBenefits Since 1997, greening, besides safety, has been the g o a l o f s lo p e m a in te n a n c e a t th e C h in e s e U n ive rsity. There are a p p ro x im a te ly 300 slopes o n the U n ive rsity campus, a hu nd red o f w h ic h have been surveyed and 60 have been stab ilized. Ir. Francis W ong , g e o te c h n ic a l e n g in e e r o f th e C am p u s Developm ent O ffice (CDO), reported that the CDO has le a rn t from years o f experience and fo u n d a slope greening m od el suitable fo r the U n iv e rs ity environm ent. The m odel takes in to account factors such as h yd ro log y, geology, slope gradient, slope d ire c tio n , an d r a in fa ll v o lu m e . Each slo p e is d iffe re n t hence greening projects are ta ilo r-m ad e a n d a im e d a t m in im iz in g im p a c t o n th e e n v ir o n m e n t . A d v ic e o n h o r t i c u l t u r a l a rra n g em e n t and cam pus e co lo g y is g iv e n b y experts from the Estates M anagem ent O ffice. The U n iv e rs ity in v ite d e xte rn a l con tra ctors to s u p p ly m odels fo r te stin g d iffe re n t green ing techniques on Residence Road to id e n tify the ideal conditions fo r g ro w in g various types o f plants. It also assists postgraduate students o f the D e pa rtm ent o f B io lo g y and the D e pa rtm e n t o f G eography and Resource M anagem en t to c a rry o u t slope veg e ta tio n research at the Sir P h ilip H a dd on-C ave Sports F ield. U n lik e go ve rnm e n t and o th e r u n its engaged in slope green ing research, the C U H K geotechnical engineering u n it has been m o n ito rin g the same batch o f slopes fo r years and therefore has a tho ro ug h un de rsta nd ing o f th e ir greening effects and m aintenance needs. Ir. W ong said the U n iv e rs ity 's w o rk has served as reference m a te ria l, especially in term s o f g re en ing effectiveness, b io d iv e rs ity and p re se rva tion , fo r m any governm ent departments and engineering consultants w h o have p a id site v isits to the U n iversity. To im p ro ve th e ir m a ste ry o f slope g re e n in g techniques, the D e p a rtm e n t o f B io lo g y and the D e p a rtm e n t o f G eo g ra p h y and Resource M anagem en t w ill organize a w o rk s h o p on 19th N o vem b e r 2005. The w o rk sh o p w ill analyse the U n iv e rs ity 's greening experience and research fin d in g s fro m a p ra ctica l p o in t o f v ie w and explore engineering issues in slope greening. P la n tin g o n s ta b iliz e d slopes poses m a n y obstacles. Besides factors related to engineering, climate, and the plants them se lve s m ean th a t g re e n in g effects canno t be q u ic k ly observed. Ir. Wong observes tha t efforts at a rtific ia l greening are som etim es n o t as good as na tu re 's fingers. ‘Vegetation planted on stabilized slopes often does no t flo u ris h like native plan ts w h ic h re tu rn to th e ir native soil b y nature's sle igh t of hand. This shows w h a t are expected o f greening technology — su sta in a b ility and re h a b ilita tio n .' ↑ Below the Tsang Shiu Tim Building, United College Simple and effective greening — two steel wires fixed horizontally on the slope act as a kind of trellis for the upward growth of bougainvillea ↑ Beside the Mong Man Wai Building Top half of the slope — on the left, fiber soil is used while, on the right, ordinary spray grass technique. The former is ideal for short growth time span and the latter is better for a longer time span. 16 Chinese University Bulletin Spring • Summer 2005