The average Metro Vancouver tree has a lifespan of less than eight years. That makes it even more important to preserve as many trees as possible. The startling statistic, from Brian Minter, a prominent B.C. horticulturist, serves as a deadly warning: Metro Vancouver’s unusually early and severe watering restrictions are a threat to the region’s trees. Given that so many young trees in Metro Vancouver do not reach their tween years — mostly for lack of watering — Minter has come to think of the metropolis’s relatively few older trees as rare and precious “gold.” …Because of lack of time, knowledge or concern, Bill Manning, retired director of horticulture for Vancouver parks said, many homeowners, tenants and strata councils don’t recognize that, though they’re not allowed to use sprinklers on trees, they are permitted to water trees by hand using a hose with a spring-loaded shut-off nozzle, a watering can, or drip irrigation.