These are a collection of the most frequently asked questions we have received. Many of the more commonly asked questions about forestry in general, are answered on the Forestry Insights web page. This is a web site designed for students, forestry industry trainees and the general public.
This page will be reviewed periodically and updated with new questions.
What tree species do City Forests grow and for what purpose?
In the past we have planted a wide variety of species but are now concentrating on three main species, radiata pine (85%), Douglas-fir (10%) and macrocarpa (5%).
Radiata pine is a very versatile timber, it has a light colour, even texture, dimensional stability, good strength to weight ratio and is easy to treat and dry. It is limited however as a result of its low-density corewood, low stiffness and low surface hardness. Radiata is processed into sawn timber, plywood and reconstituted products like chipboards and pulped for fibreboard and paper.
Douglas-fir has very good strength and stability properties and is primarily used for structural and framing timber.
Macrocarpa has a fine texture, good machining properties and is very durable and stable. The wood is suitable for a wide range of exterior uses but has a low hardness and therefore does not perform well as furniture, although it has a good appearance and is often used for furniture products.
What are the prices of logs?
The price of logs is very variable and fluctuates dramatically. For this reason the best source of up to date log prices is on the Ministry of Agriculture web page.
Where are the logs processed?
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City Forests Ltd has a dry mill wood processing complex on its site near Milton. On this site we kiln dry and further process sawn timber from a proportion of our own sawlogs.
We also supply logs to up to 14 sawmills from Christchurch to Southland.
Our chiplogs are either sent to a medium density fibreboard plant or processed at the Otago Chipmill to be exported as chip material.
Our firewood is sent to Budget Priced Firewood on Three Mile Hill.
We also maintain a monthly shipment of sawlogs to Korea.
Why is Otago and Southland radiata pine so well suited for appearance grade products?
The main reason for Otago Southland producing very good appearance grade wood is the unique climate. Most radiata pine is grown in warmer more temperate climates, allowing a year round growing season. This causes wide, hard, dark winter growth rings, leaving stripes when contrasted with the lighter and softer summer rings, thus creating a colour and density variation. Radiata grown in Otago and Southland does not have this variation because the tree shuts down for most of the winter, as it is too cold. This creates smaller winter rings and larger whiter summer rings giving the wood a creamy white appearance and even texture. These growing conditions produce a consistent fibre with minimal growth rings and a white appearance.
The unique climate of Otago Southland also produces longer internode lengths (more clear wood), less internal collapse (when drying), longer rotation (a higher percentage of outerwood to corewood), fewer internal defects (producing high appearance grade recovery), and better finishing properties (more even texture and density).
If you have more questions about forestry the following links may also be useful:
New Zealand Wood
Southern Wood Council
New Zealand Forestry
New Zealand Forest Owners Association
New Zealand Kyoto Forestry Association
Ministry of Agriculture and Forestry
Scion Research
University of Canterbury
Forestry Industry Training
Telford Rural Polytechnic
Kiwi Careers
New Zealand Institute of Forestry
National Rural Fire Authority
Also visit: CityofDunedin.com
