The long-term nature of a forestry operation requires a thorough knowledge of all the elements impacting the business, combined with careful planning and cutting-edge forestry practices. York is positioning itself as the leading plywood and saw timber producer in the country. Great strides are being made in the detailed process of matching different growing conditions with the correct variety of seedlings, including development of York’s own hybrid species.

Silviculture practices and controls are constantly being refined, which is paying off in a tight operational discipline that has become entrenched throughout the value chain. Seedling survival has improved and is being maintained at optimal levels. Weed infestations are at historically low levels. Strict controls have ensured that the quality aspects in all operations are fully maintained; and these have resulted in healthier plantations growing with increased vigour.

Exciting developments are beginning to yield dividends in the field of tree improvement, where the York Research department has made significant progress in its pine hybrid programme. The output of this research and development programme is trees that are better adapted to York site-specific conditions, more tolerant to climatic impacts, pests and diseases; as well as yielding significantly better growth and improved timber quality. This is an important strategic achievement in our competitiveness and sustainability.

Sustainable yields

York has initiated a site classification study to enhance the future value and volumes of its biological asset. This involves improving the understanding of York’s growth sites and optimising species/site matching. York’s pine and hybrid breeding programme complements this programme by providing more suitable planting material for the various sites.

This study involves understanding the interaction of tree growth response to various sites. Site types are defined primarily by soil type and depth, rainfall, temperature and topography. Uniform sites have been mapped with their attributes, allowing for optimum site/specie matching on a commercial scale. The study for the Eastern Escarpment landholdings has been completed and that of the Highveld is in the final stages. This study has allowed York to quantify the value gain that can be expected with better site/specie matching. This will also enable York to identify the site types and area involved for which no optimum match is available, which will be addressed in the future through the tree breeding programme. It is anticipated that, with the deployment of the knowledge gained from the above work, a substantial volume increase can be anticipated.

The improved updated Forest Site Data Base (FSDB) will provide the following applications:

  • A strategic spatial overview of yield potentials and qualities of the different site types;
  • Optimisation of integrated markets and timber product options;
  • Site-specific forest management;
  • Timber yield optimisation; and
  • It will also assist the research programme in identifying major site types for proportional distribution of trials, tree breeding and land improvement.

Many sites across the landholdings experience frost annually, with severity changing from year-to-year. It is therefore essential that some degree of frost-tolerance be incorporated into the tree breeding programme for all genotypes. York will develop a frost rating map across all sites in the new financial year.

Forestry sectoral determination:
minimum wage

All York’s forestry employees are paid above the minimum wage and the implementation of this legislation impacted York’s contractors rather than York’s own employees. All York’s forestry contractors are compliant with the minimum wage requirements. The minimum wage increase had a significant impact on the Forestry division’s results (R8,2 million).

As wages are expected to increase substantially in the future, it is an imperative that new innovative solutions be introduced to manage and absorb future wage increases.

In order to mitigate all of the above, York will embark on a modernisation project in the new financial year. The project will include a review of all current systems and the introduction of new technology in the forestry operations.

The objective of this project is to improve the quality of operations and to be more cost effective. It will also position York better for future cost escalations.

Typical operations taking place on a plantation in normal practical sequence are as follows:


The pine hybrid programme

Increasing volumes

Significant effort is being invested to develop pine hybrids that display superior growth and disease tolerance in comparison to York’s pure species, without compromising on wood quality.

To achieve this for Pinus (P.) species:


Cold facts

In many cases, hybrids between two parent species outperform both parents on the same site. This is known as hybrid vigour or heterosis, and is true for the abovementioned cold site hybrids. The gains that can be achieved by planting them are simply due to this phenomenon. However, growth can be further improved by identifying specific families within the hybrid which display growth better than the mean performance.

Elite families

York has, over the last number of years, invested much time in control-pollinating specific parents between P. elliottii and P. caribaea, and P. patula and P. tecunumanii, in order to identify elite family combinations. Some trials testing a limited number of specific families of these two hybrids have been planted. During the next few years, trials testing a larger number of specific family combinations will be planted.

Future forward

The commercial deployment of pine hybrids will ultimately be limited to specific families. There is no doubt that, although time-consuming and expensive, the production and deployment of specific hybrid family crosses can offer the greatest gains in terms of increased plantation yield, provided good silviculture practices are adhered to.

Furthermore, hybrids, particularly those between sub-temperate and tropical species (like P. patula and P. oocarpa respectively), will allow us to extend the planting range of each, making them adapt more readily to climate change. Some species, like P. leiophylla, offer excellent fire tolerance. Hybridising a species with good growth but poor fire tolerance, like P. patula, with a species like P. leiophylla, will reduce the risk of mortality after a fire event.

DNA fingerprinting

Genetically the best

Seed orchards are a valuable source of genetically improved seed for York’s commercial nursery and ultimately its plantations. It is therefore important that the clonal identity of selected trees in York’s breeding programme is correct. This is achieved through DNA fingerprinting, which generates a genetic profile for each clone in the orchards. In turn, seed harvesting and controlled pollination operations can then be accurately planned.


The process

Pine needles are collected from the trees in York’s orchards. These are individually labelled, packaged and sent to the Forest molecular Genetics (FMG) laboratory at the University of Pretoria. Here, DNA is extracted from the needles and a short sequence repeat (SSR) profile is generated for each sample. The number of times the SSR is repeated varies, and this can then be used to distinguish between clones. There are many different areas (loci) in the genome in which these SSRs appear. The FMG uses 11 markers (or 11 different SSR loci) to improve the power of the genetic profile.

A consensus sequence, or profile for a specific clone, is generated from a sample of which York can be sure of the identity. All subsequent samples submitted under this clone number are then compared to the consensus sequence to see if it matches or not. Alternatively, if the integrity of a specific sample is uncertain, several samples under this clone number are submitted. once three of them match, a consensus sequence is generated to which subsequent samples are compared.

To date, 213 samples from York’s P. patula orchards and trials have been submitted from which 81 consensus sequences have been generated.

Future forward

Eventually the Group aims to submit samples for all the clones in its orchards, to ensure the integrity of its breeding programme.



Reducing frost risk

York’s hybrid programme is becoming increasingly important, with frost risk reduction ranked as an important criterion in its breeding programme. The fungal plant pathogen Fusarium circinatum also continues to pose challenges for P. patula pine trees as a pure species.

Cold tolerance studies

Much of the forest on York’s Escarpment and Highveld sites is subject to sub-zero temperatures in winter. This makes it important to find quick and reliable methods to identify provenances or families within P. oocarpa and P. tecunumanii that are able to withstand cold temperatures.

There are two pollen parents currently used to produce Fusarium-resistant hybrids with P. patula for commercial deployment, P. tecunumanii and

P. oocarpa. However, both of these species originate in tropical regions of mexico and Central America and are naturally more susceptible to frost.

Three method momentum

York is currently evaluating three methods using seedling material of 165 P. oocarpa families (representing 16 provenances or locations from their native range in mexico and Central America). This evaluation will reveal the best method to use for future studies.

Ultimately York aims to determine the relative frost tolerance, not only of families of its important tropical species like P. tecunumanii and P. oocarpa, but of each of its pine hybrid families before they are commercially deployed. This will ensure that the risk of crop failure due to a severe frost event is reduced.