Trees and wind

The effects of strong winds on trees is a much-researched topic. International conferences have been conducted on the issue.

Trees bend and sway in strong winds to dissipate energy and help them withstand the onslaught without failing. Young trees that are exposed to persistent one-direction winds develop stronger root systems to resist wind loads.

The Bureau of Meteorology states, “The predominant wind stream over Victoria is of general westerly origin, although it may arrive over the State from the northwest or from the southwest. There are wide variations from this general description, however, and many northerlies or southerlies are experienced. Furthermore, the hot northerlies which bring heatwave conditions from the interior are well known, whilst in winter and spring exceptionally cold weather may accompany a southerly wind stream.”

The recent strong easterly wind Gippsland experienced was caused by the combination of a low-pressure system off the southern NSW coast and a slow-moving high-pressure system south of Tasmania. Winds travel clockwise around lows and anticlockwise around highs.

As a result of the developing pressure system, the BoM published forecasts of strong easterly winds for much of Victoria for several days in a row.

Some easterly gusts were quite strong and placed trees in this district under conditions they are not acclimatised to.

Street trees or stand-alone trees, without the protection of other nearby trees, are more exposed to wind loads. Urban trees will often have root zones that are restricted by building foundations, roads and footpaths, etc. Urban trees will often be exposed to environmental stresses that cause them to exhibit ‘old age’ characteristics years before their wild-growing relatives. Urban and stand-alone trees may not have the support of a root system entwined with other nearby trees.

Urban and stand-alone trees are often more susceptible to failure by windthrow. Trees compromised by decay or previous damage are at higher risk of wind damage.

Climate change is intensifying the strength and frequency of strong wind events by increasing atmospheric heat and moisture, leading to more violent thunderstorms, faster-intensifying cyclones, and stronger gusts.

 

 

 

The Colonel has come to Drouin

This post is not so much about the company, but more about a few its customers. Our working bees at Golden Whistler Reserve have always involved collecting roadside rubbish, including plenty from the golden arches, that other American multinational fast-food chain.

Roadside litter – food scraps, wrappers, cans and bottles, etc. – severely impacts wildlife. Animals attracted to the litter can be injured or killed by passing traffic. Ingestion of waste food can create significant health issues for wildlife. It is not unusual for birds and other animals to become trapped or entangled in plastic wrap or drink cans.

Not to mention the effect on the environment that the dumping of garden waste creates!

The answer is obvious, but will we ever learn?

Viewing platform at Bellbird Park

Dog walkers and others who use the perimeter track around the oval at Bellbird Park, may have noticed some construction proceeding at the northern end of the lake.

The Friends of Drouin’s Trees have lobbied for some time for a masterplan to upgrade the neglected area west of the lake. This location is an environmental ‘hotspot’ for Drouin. The FoDT have been conducting bird surveys in the area for some years now. The bird survey team regularly score 30-40 species in their 2-hour surveys at Bellbird Park.

The shire has developed a plan to improve access to the area. Phase one of the plan is to construct a boardwalk on the west side of the lake, upgrade the path through the tree fern section at the southern end, and to construct a viewing platform at the northern end.

Image credit BBSC

A small number of trees have had to be removed for access and safety reasons. An ecologist on site during this operation determined that the stumps remain so as not to disturb nearby Burrowing Crayfish habitat. The trees removed were placed in the lake for aquatic habitat. Some mulch was removed from the site and will be returned later when a planting program will be instigated.

Construction of the viewing platform has begun with the foundations in place. The deck, some seating and safety balustrading will be added shortly.

The shire’s construction supervisor for the project is working closely with the FoDT and is updating our group as progress is made.

More later as things develop.