Farm forester Denis Hocking likes the look of cypresses when filling gullies with trees.

I guess it is probably a spin-off from the billion trees policy and the higher profile for farm trees, but I seem to be fielding significantly more inquiries from people thinking trees. In particular, and very appropriately I think, they are wondering what they might plant in their gullies and low-productivity land.

Most of them aren’t widely enthusiastic about radiata pine and even the natives have their limits. Interestingly eucalypts seem to be a common thought, but eucalypt enthusiast that I am, my first suggestion is normally cypresses if timber is a consideration.

The best timber eucalypts don’t tend to thrive in gullies and hollows, especially if frosting is an issue. The eucalypts that do handle such sites, especially the common E. nitens, E. regnans and E. fastigata which will generally outgrow radiata pine, might be described as useful but not top timber species. Of the three, E. fastigata has the best-quality timber but poorest form. None are durable.

So why cypresses?

They have a number of advantages for gully plantings, enjoying moister, more-shaded sites and shelter from prevailing gales. Generally they do require more fertility than radiata pine and the common eucalypts.

Redwoods enjoy similar conditions and as it matures a gully planting of redwoods can become a spectacular sight. However, if timber is a priority I belong to the cypress school rather than redwood fan club. This will immediately raise hackles in some quarters and I accept there is room for debate.

Cypresses have a number of virtues as timber trees – notably ease of milling, stability, moderate to good durability, versatility and in many cases, attractive appearance. They can be milled any time from late teens to 100 years-plus though there may be problems at the extremes.

Macrocarpa, Cupressus macrocarpa, has long been the cypress flagship in New Zealand, and is still the market favourite, followed by C. lusitanica and Chamaecyparis lawsoniana. However, as most readers will know, the fungal disease cypress canker has increasingly restricted the performance of macrocarpa while lusitanica tends to have a rather variable reception in the market.

Lawson cypress has very good timber but only seems to perform in inland, higher-altitude sites.

However, I don’t usually recommend these three, although I will recommend macrocarpa on good sites if you have a proven canker-resistant provenance. There are such provenances, but be cautious.

My recommendations centre on the hybrid cypresses and especially the Ovensii hybrid between C. lusitanica and Chamaecyparis nootkatensis – Alaskan yellow cedar. This latter species is a highly regarded, extremely durable but also slow-growing tree revered from south-eastern Alaska to Washington State.

The better-established Ch. nootkatensis x C. macrocarpa hybrid, the Leyland cypress, is common in NZ, mainly as shelter, and although not widely recognised as a timber option it does mill extremely well, is remarkably stable and appears to have better durability than macrocarpa. Sadly it is also a bland, yellowish timber and doesn’t have the visual appeal of macrocarpa, but for outdoor uses, including decking, it is a better bet.

Ovensii timber is very similar to Leyland, though not a great deal has been cut in NZ to date. But it is the form and health of the trees that really appeal, along with good growth rates on better sites – like gullies.

My enthusiasm also reflects the very limited plantings of cypresses in recent years. It is estimated that only about 500 hectares of cypresses were planted in the last five years, hardly appropriate for such high-quality, versatile timbers.

The research effort is also very limited. Scion’s main effort at present is creating and trialling new hybrid clones but the problem is that it will be a decade or more before we will know if they are any better than what we already have. Scion is also breeding for canker resistance in macrocarpa and general improvement in lusitanica.

So please excuse any bias on my part, but I still think cypresses are a good option for those gully plantings. I hope you can agree.