In the 1990s, scientists and others acknowledged that New Zealand needed more than one species to meet the huge variety of demands for timber. Eucalypts were already growing all over the country. The quest was to identify the most productive species for New Zealand conditions and learn more about their growing and processing behaviour and timber properties. 

1991 – FRI work on stringybarks begins: The NZ Forest Research Institute (now Scion) was interested in stringybark eucalypts as a potential high-value alternative for sawlog production. In 1991 the Special Purpose Species group of the FRI included naturally durable species in its programme (McKenzie, 1993 - see Key References). The group recognised that international concern over the depletion of tropical rainforests would affect consumer choice and that plantation-grown durable eucalypts could be substituted in these markets. Also, that while there had been a long history of introductions and planting by pioneering farm foresters, little research had been undertaken into evaluating the growth of these species, and identifying the best seed sources, site requirements and spacing regimes.

Eight species were identified for evaluation including four durable eucalypt species (E. pilularis, E. muelleriana, E. globoidea, E. microcorys). Existing stands were surveyed to help develop genetic and silvicultural trials. In 1994, E. muelleriana was planted into two provenance trials in Northland and the Bay of Plenty. These were the first breeding trials of a durable eucalypt species in New Zealand.

1996 - Neil Barr, founder of the NZ Farm Forestry Association, tested many species and in his book ’Growing Eucalypt Trees for Milling on New Zealand Farms’ (1996) he recommended three well-proven durable stringybark species - E. pilularis, E. muelleriana and E. globoidea - that he and others had grown for both naturally durable posts and poles and  high quality sawn timber. His book is still available from the NZFFA. 

1997 – Durability testing by NZ Forest Research Institute:  The NZ work was similar to CSIRO durability work, and results were summarised by Page et al. in What’s New in Forest Research bulletin 245 (1997) (available here with thanks to Scion).

E. cladocalyx and E. cornuta were the only class 1 species identified, while E. amygdalina, E. botryoides, E. globoidea, E. muelleriana, E. pilularis, E. saligna, E. microcorys and E. radiata were placed in class 2. The classification of E. botryoides, E. muelleriana, and E. saligna is higher than that assessed in Australia for the same species, while E. microcorys was assessed as a class 2 durable whereas in Australia it is class 1.

CSIRO wood durability research work over many decades underpins the Australian Durability Standard , last updated in 2005.  

1999 – the Australian Low Rainfall Tree Improvement Group (ALRTIG): work begins to try and increase tree planting on Australian drylands. Key areas included breeding initiatives and market development work:

“ALRTIG’s goal, since its formation in 1999, has been to develop and genetically improve tree species that are both well-adapted to this region, and that will produce commercially valuable products in tandem with environmental outcomes.”

ALRTIG’s selected species included a number of durable eucalypts, and their work provided an important early model for some of the NZDFI’s initiatives. Improved E. cladocalyx seed developed through the ALRTIG programme has been widely tested in many NZDFI trials and is proving a species well adapted to warm drier regions of NZ. 

ALRTIG's E cladocalyx factsheet is a recommended reference document.

Some of ALRTIG’s other publications can be found here.