Trees for Bees 2014

The Trees for Bees New Zealand campaign was launched in 2009, and aims to enhance pollination on farms and orchards by providing a wider range of forage food sources for bees. The results to date have included research and publication of tree species suitable for planting that provide abundant nectar and high-quality pollen. This is especially important during critical seasons, mainly spring and autumn to help bees resist disease, pests and exposure to pesticides, as well as improve pollination services and the honey flows for apiarists. Eastwoodhill near Gisborne is the National Arboretum containing 1,663 species and more than 5,000 cultivars of mainly northern hemisphere deciduous trees and some NZ natives. The present phase of research work at Eastwood Hill Arboretum is to search for suitable bee fodder in autumn.

The Trees for Bees campaign was initiated in 2009 by Federated Farmers of New Zealand and Linda Newstrom-Lloyd at Landcare Research, a Crown Research Institute. Based on this work, the Bee Friendly Farming Group (BFFG) with Ross Little as Chair was formed with several farmers and beekeepers on the project team and new partnerships added including the National Beekeepers’ Association, AsureQuality, GNS Science, Foundation for Arable Research (FAR) and many beekeeping and honey companies.

Since 2010, the Trees for Bees Project of the BFFG has been fully supported by funding from the MPI Sustainable Farming Fund. The initial campaign in 2009 published 10 regional guides, four for the North Island and six for the South Island. They contain recommendations for highly ranked flowering tree and shrub species that are suitable for farm planting. These 10 Federated Farmers Bee Plant Guides represent a selection of the best bee plants based on current beekeeper evaluations, advice on elimination of weeds, regional distributions of high-ranking plants, and compatibility with farm situations.

The regional lists were combined into a national list of 98 key species with a flowering calendar in Chapter 2.11 of the Ecosystem Services of New Zealand book recently published by Landcare Research. The 2009 bee plant lists did not have many exotic species included and scarce information about protein content was then available. To remedy these gaps, the Trees for Bees Team have searched for suitable exotic plants that can also be used by farmers. The Eastwoodhill National Arboretum has become the centre of this search because it contains 1,663 diverse tree and shrub species from all over the world especially north temperate trees.

After two years of working in the arboretum, the Trees for Bees team has accumulated new lists of suitable species for farms i.e. low maintenance and for gardens. In addition, the team has processed the pollen from these species at Eastwoodhill and surrounding areas in Gisborne to determine the protein content. The list of plants now includes over 100 species that have been analysed for protein level in the pollen and another 136 species are in the process of being analysed.

Bees consume pollen as a protein and vitamin source and nectar for energy. Availability of protein-rich pollen is critical during spring when beekeepers are building up their bee colonies for pollination services and honey harvesting. Any protein shortfall leads to weakened bees and population crashes making the bees susceptible to pests and diseases. It also dramatically slows the queen’s breeding output and results in under-performing pollination services.

The emergence of treatment resistance by the ubiquitous and deleterious varroa mite has made bee health a top priority for New Zealand’s agriculture. Of all the food we eat, about a third of the calories and three-quarters of the diversity rely on bees for pollination. In NZ $5 billion of our GDP is attributable to pollination services by bees for kiwifruit, apples, avocados, seed production and clover regeneration. The protein that is supplied by pollen is therefore a critical resource for agriculture.

Making sure farms have the required diversity and abundance of pollen sources for bees throughout the year is an important part of the Trees for Bees research. To this end, the project has already installed 5 demonstration farms and is in the process of installing five more including small and large scale farms of many types. The bee plants that are installed are strategically selected to fill in the pollen supply gaps that are so detrimental to bee populations. This means that more bee colonies with more abundant and healthier stronger bees will be available for pollination services to sustain farmers and growers into the future.

Eastwoodhill is the National Arboretum for New Zealand. It consists of 135ha of exotic and native trees, shrubs and climbers. In 1910, local farmer William Douglas Cook began to bring in northern hemisphere trees and shrubs (an estimated 5000 species and cultivars) to create the largest collection in the Southern Hemisphere. Many would not be imported today because of the biosecurity regulations and the time and effort involved in gaining permission. Eastwoodhill is a national treasure of mainly English species like oak, ash, maple, conifers (pinus), fruit trees (prunus), azaleas and rhododendrons. Because there are many varieties of each genus, their form, site preferences, growing rates and flowering times can be catalogued and the suitability as protein and energy sources for bees can be measured. While the preference for Trees for Bees recommendations are native trees and shrubs, exotics can fill gaps such as in October after willow and before clover (when ashes, oaks and maples are flowering). The hives at Eastwoodhill belong to Barry Foster.

Researchers have used pollen traps on bee hives to sample what the bees are feeding on, which is then analysed for protein content. Some flowering trees have very high protein content, above 25%, while others like pine have less than 10%, which is insufficient for good bee colony health. Some natives have high protein levels, such as flax flowers (32%), cabbage tree flowers (28%) and five-finger (20%). Protein values for 163 species have been measured to date, including some forbidden plants like gorse and broom (35%).

A second research programme under the Bee Friendly Farming Group focused on finding the most nutritious plants that flower in the two critical pollen-dearth times – autumn, when bees are preparing to over-winter, and late winter/early spring. Traditional forage plants at those times like gorse and broom are invasive, introduced species which are now being controlled and removed. This second project is also looking for the highest protein levels because protein is hard to supplementary feed to hives.

Many types of farms have pockets or strips of unproductive land that could be used to plant bee forage species that have multiple other uses to benefit the farmer. With the right choice of plant species, areas in riparian strips, gullies susceptible to erosion, around irrigation or effluent ponds and other unusable marginal land can be used to plant bee forage plants that will both benefit pollination on the farm and meet other planting goals.

Linda Newstrom-Lloyd is keen to find protein supplies to fill the April/May pollen dearth. As Linda points out, if farmers need clover pollination or crop pollination for seed production, or arable or horticulture crops that need pollination, they would depend on the honey bee. “There is no other industrial scale pollinator in New Zealand that can do the job that the honeybees do.” So if farmers cut out bee forage and reduce or weaken bee populations through starvation, then they are hurting their own crop or pasture yields.

For the second stage of the Trees for Bees research and trial programme bee forage plots have been planted on 5 farms and a further 10 sites have been assessed and will be planted soon. The number of stems planted (trees, shrubs, and low shrubs) is now approaching 10,000, on slightly less than 10ha in total. The project team has planted on one large and small scale sheep and beef farm, a mixed livestock and cropping farm, an orchard and an arable cropping farm. Beekeepers’ queen raising and mating yards have also been planted on farms, as well as a public park with a regional council.

The demonstration farm belonging to Peter Hair, at Patutahi, has tree lucerne on very dry sites, native hebes, fennel and lavender, some of which are flowering in autumn. Paul Badger is a beekeeper with hives on the Hair farm. A farmer initiated technology transfer project supported by a grant from Beef & Lamb New Zealand aims to change the pasture area on the farm from an undesirable beekeeping area through the introduction of improved bee foraging plants with high-protein pollen as well as nectar. The hives are set onto weighing units, which can send daily readings via satellite to a computer to be graphed. From this information Paul Badger and entomologist John McLean can see what difference three small “food factory” areas of paddock planted with a variety of shrubs, trees and herbs make to the health and production of bees on different feed sources.