From The Supply Post Archives: Snipping Sniper

May 19, 2021 - 5 years ago

Snipping Sniper

MacMillan Bloedel foresters are matching up “super trees” as potential parents in a comprehensive tree improvement program for British Columbia’s coastal softwood forests.

Silviculturist Rod Stevens, who heads MB’s tree improvement program, says the company plans to grow entire forests of genetically superior trees of several different species, now that some of the basic lessons have been learned in lengthy government-industry research program on Douglas fir.

“Basically, it’s planned parenthood for trees, with our foresters and scientists playing a role similar to that of marriage counsellors,” said Stevens. “The aim is to produce genetically improved seed which will be used to reforest harvested lands with faster growing, better forests of different species.”

Until recently most tree improvement work concentrated on Douglas fir because of its importance to the B.C. forest products industry. Research was conducted on an industry-wide basis, with the full co-operation of several federal and provincial government agencies.

Now MB foresters and those of other companies have started identifying for breeding stock “plus trees” in stands of hemlock, Sitka spruce, shore pine, white pine, amabalis fir and western red cedar, as well as continuing development of the Douglas fir.

They are approaching tree improvement problems equipped with the same basic genetic principles that have enabled man to greatly improve strains of grain, fruit, vegetables, and livestock. In essence, it’s selective breeding.

Stevens sees tree improvement as a long-term investment in the future. The first genetically improved plus tree forests won’t reach maturity in British Columbia coastal areas for at least another 75 years.

“Selection of plus trees is the critical first step in our program, and it’s not as easy as it sounds,” said the silviculturist. “In fact, it’s extremely rare to find a candidate that excels in all traits — height, stem diameter, straightness, branching characteristics and general form.”

Stevens said forestry personnel spend several weeks each summer checking vigorous 40-to-70-year-old timber stands looking for “really outstanding specimens” superior to their neighbours of comparable age.

“Selecting plus trees can be quite subjective. We get into some lively debates among ourselves, advocating the merits of various candidates.”

Selection of Douglas fir plus trees began 16 years ago under the auspices of the Tree Improvement Board, an association of government, industry and University of B.C. Foresters. To date, approximately 550 Douglas fir plus trees have been identified by the companies and agencies involved in the program and registered with the board.

More recently, MB foresters have been selecting plus trees in others major species. So far, they have identified 47 western hemlock, 20 Sitka spruce, 24 shore pine, 15 white pine, and 11 cottonwood plus trees, and this year they are adding western red cedar and amabalis fir to the list.

“The mountainous terrain of Vancouver Island, the mainland coast and the Queen Charlotte Islands represent many variations in climate, soil and vegetation,” said the silviculturist.

“Foresters have to decide which species is the best for a particular site. We want to be able to offer genetically improved seed of all these species so that our foresters are able to plant not only the species best suited to the site, but the best trees of that species.”

Following summertime identification of plus trees, MB foresters returns in the late fall of early winter to collect branch tips from high in the crown of each specimen. The safest way of getting this material is by shooting off branches with a .22 calibre rifle equipped with a telescopic sight.

“It’s frustrating trying to hit a quarter-inch-diameter limb 130 feet above the ground in the swaying top of a plus tree, especially when it’s raining buckets and your scope has fogged up,” said Stevens. “But this is still the most practical way of doing it.”

Stevens said success of the tree improvement program hinges to a large extent on cooperation among the major forest product companies and government agencies, including the B.C. Forest Service, the Canadian Forest Service and the federal agriculture department.

The companies regularly trade plus tree cuttings and research data. The government agencies are involved in a number of research projects on tree improvement and the results obtained in these projects are “proving of invaluable assistance” to MB and other companies in terms of utilizing plus trees to realize intensive forest management objectives.

“To ensure efficiency and maximum genetic gain, we’ve got to have a concerted cooperative effort in the identification and propagation of plus trees,” said Stevens.

The branches from the plus trees go the company’s tree improvement centre near this Vancouver island city for propagation by grafting or rooting. In the first method, short shoots called scions are grafted onto two or three year old seedling.

As the scion grows, the host seedling’s limbs are gradually removed, affording the foliage of the plus tree the opportunity to develop. This foliage is genetically identical to the plus tree from which it came.

Cuttings from many tree species can be stimulated to produce their own root systems. Generally, the cutting is treated with a hormone solution, then provided with optimum soil and climatic conditions in a greenhouse. When the tree has developed a large enough root system it is transplanted outside.

The initial objective is to grow five cuttings or grafts from each plus tree, which are then referred to collectively as a clone — a group of genetically identical organisms produced from a single individual.

All of the clones from a similar environment are planted together in a clonebank, where the plants are preserved for breeding experiments and as a source of additional grafting material. MB now has 443 Douglas fir, 23 hemlock, and six Sitka spruce clones at the tree improvement centre. It also has 10 cottonwood plus tree clones for eventual use in soil stabilization programs.

When enough have been propagated the clones will be planted in seed orchards. MB plans to develop the first two of five planned Douglas fir seed orchards south of Nanaimo late this year or early in 1976.

The seed orchards are being designed to maximize opportunities for cross-pollination among the clones, since crossing of two individuals from the same clone can results in dwarfed seedling of other defects common to inbreeding.

Because a rooted cutting or graft is the same physical age as the tree from which it comes, it will produce cones much faster than a tree of the same size grown from seed. Use of rooted cuttings in place of seedlings greatly increased the short-term seed production capacity of an orchard.

Cones produced int he orchards will be collected and the seed extracted and sown at B.C. Forest Service nurseries. Finally, the resulting seedlings — potentially as good as, or superior to their parents — will be planted in logged areas and managed for a complete rotation of 75 to 80 years.

Although the company initially plans to utilize the seed produced in orchards for reforestation, Stevens says the option of producing a large volume of rooted cuttings for planting in harvested areas does exist.

An important aspect of Stevens’ “planned parenthood” is genetic quality control, accomplished by evaluating the growth rate and other traits of seedlings that result from carefully controlled crosses between clones. Special plantations of these seedlings, called progeny tests, are being established on the major types of planting sites.

Results of these tests will be used to rank the genetic value of their plus tree parents. Inferior parents will be culled from the seed orchards while high-ranking members will be retained for use in improved, second-generation orchards. In addition, new plus trees will continue to be selected and evaluated for possible inclusion in the tree improvement program.

This article first appeared in Supply Post, June/July 1975.

Plus Tree Seed Genetics In The 21st Century

The original Plus Tree program was a precursor to today’s robust and successful tree health improvement program. By Linda Horn

Forest genetics activities in British Columbia have been coordinated through cooperatives beginning with the Plus Tree Board in the 1960s and the Coastal and Interior Tree Improvement Councils (TICs) from the 1970s to 1997, renamed Forest Genetics Council of BC (FGC) in November 1998. FGC remains one of the most enduring and successful forest genetics programs in North America, along with the Tree Seed Centre, the primary provider of cone and seed services to B.C.’s forest industry and B.C. government staff.

Douglas-fir conelets and pollen buds in Orchard 199. Photo courtesy Forest Genetics BC.

All Things Cone & Seed

The Tree Seed Centre (TSC) is currently located on 6.7 hectares in south Surrey, BC. A little over 50 years ago, the British Columbia Forest Service began operating a provincial seed centre in Duncan on Vancouver Island. By the late 1970s, operations at the Duncan location were significantly constrained as a result of infrastructure age, size, production capabilities, capacity to handle various species and seedlot sizes, and physical proximity to clients or service providers. In the mid-1980s design and construction of a new facility specifically designed for the delivery of cone and seed services was completed. In 1986, operations were closed in Duncan and resumed in Surrey.

“The program has come a long way in 45 years,” said Dave Kolotelo, RPF, Cone and Seed Improvement Officer at TSC. “The Centre is still active in supporting this program in terms of processing cones and seeds, testing seed; storing seed, preparing seed for nursery sowing, genetic conservation, and assisting with research and extension.”

Seed Storage

The TSC is responsible for storage and maintenance of seed under optimum conditions. On average, each year 4,000 kilograms, the equivalent of 459 million potential trees, are deposited and 2,700 kilograms are withdrawn from long-term seed storage. The seed inventory also has an important risk management role in the event of catastrophic losses resulting from wildfire, insects, disease and climate change, and includes a dedicated seed bank for genetic conservation purposes.

Plus Tree Update

“As the current coastal Douglas-fir geneticist for the province, I am carrying on the research that began with the Plus Tree selection program 61 years ago and that has continued uninterrupted to this day,” said Jon Degner, A.Ag., Coastal Tree Breeder for Forest Improvement and Research Management Branch of the Ministry of Forests, Lands, Natural Resource Operations, and Rural Development in Saanichton. “While our understanding of forest genetics has changed substantially since then, the Plus Tree selection program of the past has formed the foundation upon which our current tree selection programs sit,” Degner continued.

Plus Tree Beginnings

“Alan Orr-Ewing, the province’s first forest geneticist, initiated the Plus Tree program in 1959 and recruited industry and academic foresters to the cause of finding ideal timber trees that could be used for reforestation,” Degner said. “By the time this article was written (see page 48), Chris Heaman had taken over the program, and continued to seek out exceptional trees in the field,” he continued. “While the article mentions that 550 Douglas-fir Plus Trees had been selected in 1975, we now have over 1200 Plus Trees in our program. Of these, 657 have been evaluated scientifically in controlled breeding programs.”

Plus Trees, Plus More

Degner continued, “Today, Plus Tree selection is considered only the first step of a tree selection program. We learned quickly that a single exceptional tree in the field does not necessarily translate to a good parent in a seed orchard,” he explained. “Often times, these selections turned out to be mediocre or poor growers that happened to have an especially good patch of land to grow on, and so outperformed their neighbours. Ultimately, we got little improvement in timber qualities from these Plus Tree programs, but they provided us with a broad sample of unrelated trees from all over the species range that could be cross-bred and evaluated. Fifty-two coastal Douglas-fir Plus Trees that were found to have truly exceptional timber traits are still used in today’s seed orchards, but the majority of the trees used in modern orchards come from the descendants of these original selections.”

Plus Tree Parentage

“In 1975, Chris Heaman was developing the province’s first tree breeding program, which would, over the next decade, directly evaluated many of these Plus Trees as parents in crosses with other Plus Trees. This is what we consider the first generation of the breeding program. Just last year we established the first trials from our third generation breeding program, producing the great-grandchildren of these Plus Trees,” said Degner.

“A lot has changed since then,” said Degner. “While industry and academia are still strong partners in our tree selection programs, the bulk of genetic selection research in BC today is done by the provincial government. While private companies own and operate seed orchards, they use genetically-improved trees from provincial research programs. One important relationship from that era that remains today is that our industry partners have always been very helpful in selecting test sites and allowing us use of their forest lands to establish our research trials.”

Tree Improvement

“Perhaps the biggest change is the scope and intensity of genetic selection in BC,” remarked Degner. “The 1975 article mentions coastal Douglas-fir as the major tree selection program, with a handful of other coastal species’ programs in their infancy. Today, we have tree selection programs covering all major forestry species on the coast and in the interior. All of these programs started with Plus Tree selection, and have since moved into breeding programs to accurately evaluate the performance of trees as parents in seed orchards. We have also changed our goals in “tree improvement”. While the first Plus Trees were selected for optimal growth and form, we now also regularly evaluate trees for resistance to economically-important diseases and pests, and wood quality. Our coastal tree selection programs are also starting to evaluate drought resistance as this is becoming an increasing concern in our coastal forests,” he explained.

How Successful Was The Plus Tree Program?

“Very,” said Degner. “The Plus Tree selection program heralded a revolution in how we reforest BC, and sparked research that continues today. In 2019, BC nurseries sowed 308 million seedlings for reforestation. Of those, 180 million (almost 60%) came from seed produced by seed orchards with genetically-selected material from these selection and breeding programs,” he concluded.

Further Reading

The Forest Genetics Council

Tree Seed Centre

Whitebark Pine Workshop