Conifers: Species Diversity and Improvement Status in Kenya

A wide range of exotic conifer species have been successfully introduced in Kenya since 1910 for the purpose of supplying wood, mainly for timber, pulp, and plywood industries. Among the conifers introduced, Cupressus lusitanica and Pinus patula have adapted well to local growing conditions and are now the key species widely planted in commercial plantations. The other conifer species are planted at secondary level or as ornamentals. In order to increase productivity, the key conifer species have been subjected to genetic improvement through selection, breeding, and hybridization. Results of tree improvement work on C. lusitanica and P. patula showed growth and productivity increase from 20 to 25 m3/ha/yr. for C. lusitanica and from 25 to 30 m3/ha/yr. for P. patula. Scaling up conifer plantations using the tree improvement technologies drawn for the two species is one of the strategies for closing the annual wood supply–demand deficit which is currently estimated at 10.3 million m3. It is also one of the strategies for achieving 10% tree cover which is currently at 7.2%. The strategy encompasses the application of principles of tree breeding, improved germplasm, silviculture, pests and disease control. This presentation is a review of the status of conifer species since their introduction in Kenya.

Near-infrared spectroscopy and hyperspectral imaging can aid in the prediction and mapping of polyploid acacia hybrid wood properties in tree improvement programs

Acacia, including Acacia hybrids, are some of the most important species grown as part of the Vietnamese wood industry. Rapid methods to identify the variations in the wood properties of Acacia hybrids however, are a currently lacking and creating limits for their breeding programs. In this study, nine Acacia hybrid clones, including those that were diploid, triploid, and tetraploid were evaluated using near-infrared spectroscopy (NIR) and hyperspectral imaging (HSI). The standard normal variate (SNV) and second derivative (SP2D) were applied to compare the performances of NIR and HSI using partial least square regression. The HSI images were acquired at wavelengths from 1033 to 2230 nm and the SNV and SP2D described the variations in the wood properties. The NIR predicted the wood physical properties better than HSI, while they provided similar predictions for the mechanical properties. The mapping results showed low densities around the pith area and high densities near the bark. They also revealed that the air-dry moisture content changed at different positions within a disk and was dependent on its position within the tree. Overall, NIR and HSI were found to be potential wood property prediction tools, suitable for use in tree improvement programs.

Screening of Mango Rootstock For Saline Tolerance

An experiment was conducted at Fruit Tree Improvement Project, Fruit Tree Improvement Programme, Bangladesh Agricultural University-Germplasm Center (FTIP, BAU-GPC), Bangladesh Agricultural University (BAU), Mymensingh during the period of April 2020 to June 2020 to study the performance of selected mango rootstocks for the saline area. The two-factor experiment consisted of four mango rootstock varieties such as V1 = BAU Aam-9, V2 = BAU Aam-6, V3 = BAU Aam-4 and V4 = Amropali and six salinity treatments namely control S1 = 0 dSm-1, S2 = 4 dSm-1, S3 = 8 dSm-1, S4 = 10 dSm-1, S5 = 12 dSm-1 and S6 = 14 dSm-1. The experiment was conducted following randomized complete block design with three replications. Results revealed that rootstock line and salinity levels had significant influences on various rootstock characters viz. length of rootstocks, number of leaves and percent rootstocks success and survivability. In case of varietal effect, the highest number of leaves (32.44) found in BAU Aam-6 and the lowest number of leaves was recorded in Amropali (22.55) at 90 days after transplanting. The longest rootstock length observed in 90 DAT which (54.83 cm) found in BAU Aam-9and shortest rootstock recorded in Amropali (47.94 cm). The highest survivability (51.44%) was recorded in BAU Aam-9 and the lowest survivability recorded in Amropali (33.88%). In case of salinity treatments, the highest survivability (95.83%) was recorded in control and the lowest survivability (0.00%) recorded in 14 dsm-1 at 90 DAT. Interaction of rootstock varieties and different salinity treatments showed significant variation on the length leave and survivability of rootstocks at 90 DAT. The maximum number of rootstock leaves recorded in V2S2 (46.33) and lowest number of leave recorded in V4S6 (7.66). The highest rootstock length was found in V1S3 (78.00 cm) and lowest in V1S2 (21.66 cm). The highest Survivability (100 %) observed in V1S1, V1S2, V2S1, V2S2 and V4S1. From the above mentioned it can be said BAU Aam - 9 and BAU Aam – 6 rootstock varieties performed best from 0-8 dSm-1 salinity. The overall salinity tolerance was graded as follows: BAU Aam - 9>BAU Aam – 6> BAU Aam-4>Amropali rootstock line. SAARC J. Agric., 19(1): 93-102 (2021)

Establishment of Regional Phytoremediation Buffer Systems for Ecological Restoration in the Great Lakes Basin, USA. II. New Clones Show Exceptional Promise

Poplar tree improvement strategies are needed to enhance ecosystem services’ provisioning and achieve phytoremediation objectives. We evaluated the establishment potential of new poplar clones developed at the University of Minnesota Duluth, Natural Resources Research Institute (NRRI) from sixteen phytoremediation buffer systems (phyto buffers) (buffer groups: 2017 × 6; 2018 × 5; 2019 × 5) throughout the Lake Superior and Lake Michigan watersheds. We divided clones into Experimental (testing stage genotypes) and Common (commercial and/or research genotypes) clone groups and compared them with each other and each NRRI clone (NRRI group) at the phyto buffers. We tested for differences in clone groups, phyto buffers, and their interactions for survival, health, height, diameter, and volume from ages one to four years. First-year survival was 97.1%, with 95.5%, 96.2%, and 99.6% for the 2017, 2018, and 2019 buffer groups, respectively. All trees had optimal health. Fourth-year mean annual increment of 2017 buffer group trees ranged from 2.66 ± 0.18 to 3.65 ± 0.17 Mg ha−1 yr−1. NRRI clones ‘99038022’ and ‘9732-31’ exhibited exceptional survival and growth across eleven and ten phyto buffers, respectively, for all years. These approaches advance poplar tree improvement efforts throughout the region, continent, and world, with methods informing clonal selection for multiple end-uses, including phytotechnologies.

Wood supply challenges in Alberta – Growing more timber is the only sustainable solution

The industrial wood supply from public lands is at risk in Alberta from natural disturbances and landbase withdrawals while simultaneously being asked to provide for an increasing timber harvest rate. While maintaining the timber landbase is critical, we believe that the only truly sustainable way of increasing wood supply is by growing more wood. Meeting these wood supply goals will require the application of tree improvement and intensive silviculture programs on the best sites to increase timber productivity, reduce rotation lengths, and close timber supply gaps. In this article, we present the main ideas from a recent Canadian Institute of Forestry – Rocky Mountain Section workshop on wood supply in Alberta and provide what we see as the best path forward to meeting our wood supply goals – growing more timber.

Syzygium grande (sea apple).

S. grande is a moderately fast growing tree (up to 30 m tall) with natural populations in Bangladesh, India, Indonesia, Malaysia, Myanmar and Thailand. It is planted in hill forests in Bangladesh. It has good timber for poles, railway sleepers and carriage bodies. The mature trees tolerate fire and have been used in fire-breaks in Malaysia. It has a good regeneration capacity. There are about 70 fruits per kilogram (110-115 seeds per kilogram). Seed viability is short (15-25 days). About 60-70% of seeds germinate after direct sowing. In nurseries, seed germination can increase to 75-80% when raised in polybags. It coppices well when young, but coppicing ability declines with age. It can also be propagated vegetatively through grafting and air-layering. The Bangladesh Forest Research Institute (BFRI) has selected Provisional Plus Trees, established clonal orchards and identified seed production areas for tree improvement. At 45 years rotation the MAI recorded from Bangladesh is 5.4 cubic metres per hectare. More research is needed on its genetic variation and assessment of different provenances.

Genetics and Improvement of Forest Trees

Forest tree improvement has mainly been implemented to enhance the productivity of artificial forests [...]

Economic Significance of Continued Improvement of Loblolly Pine Genetics and Its Efficient Deployment to Landowners in the Southern United States

The economic consequence of continuing or increasing the tree improvement efforts for loblolly pine (Pinus taeda L.) in the southern United States is immense. For the more than one million acres planted each year with germplasm from the North Carolina State University Cooperative Tree Improvement Program, the present value of continuing current tree breeding efforts and deploying the genetic gains to landowners is estimated to be more than $1.7 billion at current prices. The present value of increasing the rate of genetic gain from 1% per year to 1.1% per year is $211 million. These analyses can be used to justify maintaining and even increasing efforts in tree improvement. With the aggressive fourth-cycle breeding program underway and plans for fifth-cycle breeding and deployment strategies being developed, we have every reason to believe that this trend for at least 1% gain per year will continue for decades, provided the resources to continue tree improvement efforts remain available. Even a modest increase in genetic gain per year would be justification for stakeholders to invest more than $12 million per year to realize this gain. Study Implications Given the tremendous economic incentives to increase the genetic quality of loblolly pine seedlings to landowners, tree breeders will continue to improve breeding strategies and deployment options to ensure that plantations provide sustained value for decades to come. Although this analysis looks at the value gains from a landowner’s perspective, the financial gains from wood supply increases will be distributed through the wood-product supply chain and will likely affect future market conditions. Future mill capacity decisions will be affected by more productive forests (i.e., supply may help create more demand). Although increased wood supply does not always benefit landowners as a whole, those landowners who have planted higher-quality, faster-growing genetic stock should have a competitive advantage over other landowners who do not invest in better quality genetics.