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Kahikatea (Dacrycarpus dacrydioides) is a tall, wetland‐tolerant native podocarp tree that has potential for restoration of New Zealand wetlands currently dominated by invasive Grey willow (Salix cinerea). We investigated methods to jump‐start establishment of Kahikatea saplings in the Ramsar‐listed Whangamarino Wetland. Treatments involved planting saplings after full herbicide clearance of the willow canopy (FULL), partial herbicide clearance of the canopy (PARTIAL), and manual cutting of light wells (MANUAL). Saplings were planted as individuals or clusters of seven. Treatment plots were established in 2015 and monitored until 2020. Despite Kahikatea being considered a "light‐demanding" species, saplings grew best in the PARTIAL treatment which had the lowest ambient light levels (x̄=32% of non‐intercepted sunlight). PARTIAL treatment saplings were estimated to require 24–36 years to reach the height of the surrounding willow canopy if they maintained similar growth rates. Preconditioning saplings by soaking roots before planting provided a growth advantage in the PARTIAL treatment plots, whereas nonconditioned plants grew better in the higher‐light MANUAL and FULL plots. No benefit was found for cluster planting. Restoration toward a native Kahikatea‐dominated forest will be contingent on saplings reaching willow canopy height before the faster‐growing willows reestablish, or periodic management of willows to maintain light levels above the compensation point for continued growth. Ultimately, the utility of this approach depends on what on‐going facilitation is required and whether seedlings subsequently produced by these emergent podocarp "islands" are able to jump‐start a long‐term change in the successional trajectory of the surrounding willow‐dominated wetland. [ABSTRACT FROM AUTHOR]

The giant willow aphid (Tuberolachnus salignus) is an invasive pest that can attain large populations on willows (Salix spp.). This has the potential to have a negative impact on the extensive use of willows for soil conservation, and as a source of pollen and nectar for honey bees in New Zealand.A willow nursery field trial was established to evaluate the aphid populations, and the survival and growth of young plants of several willow species and hybrids, during two growing seasons from planting.The willow species and hybrids varied widely in their susceptibility to the aphid, with large aphid populations and plant mortality in the most susceptible willows, and reductions in plant growth in all but aphid‐resistant willows. The effects on the plants were not seen in the first season, but occurred during the second season.The aphid can be expected to have some negative impacts in New Zealand, with reductions in growth of some willows commonly used for soil conservation, and for pollen and nectar for honey bees. [ABSTRACT FROM AUTHOR]

The giant willow aphid Tuberolachnus salignus is an invasive pest in New Zealand, attacking over 50 species and hybrids of willow. The aphids produce copious amounts of honeydew, which is used by other insects as a food source.When foraged by honeybees, T. salignus honeydew causes honey to crystallize in the comb and affects bee health; these effects are associated with the elevated melezitose content in the honeydew. The impact of host plant‐related factors on T. salignus honeydew melezitose content remains unknown.This study investigated the effect of willow cultivar and plant age on the melezitose content (and that of other sugars) of T. salignus honeydew. To do so, we conducted high‐performance liquid chromatography analyses of honeydew samples from 13 willow clones collected in the same season (autumn) from 1‐ and 2‐year old plants under field conditions.Melezitose was the most abundant of the measured sugars in most samples, but its content did not vary significantly with willow cultivar or plant age. By contrast, sucrose was significantly affected by both factors. Fructose and glucose were significantly impacted by willow plant age and cultivar, respectively. A significant cultivar*age interaction was observed for all sugars.We recommend the selection of resistant willow cultivars and further research on potential biocontrol agents to lessen melezitose‐related problems in apiculture industries. [ABSTRACT FROM AUTHOR]

The giant willow aphid Tuberolachnus salignus Gmelin is a large phloem‐feeding insect which colonizes the stems of willow trees. This aphid is a new invasive species in New Zealand and there is limited knowledge of its inter‐annual population patterns and the damage it can cause to willow hosts. Our study investigated the T. salignus population dynamics and its effects on the flowering parameters of fifteen willow species and hybrids in a field trial. The aphid population levels were found to vary among the willow species and hybrids. Based on the aphid population levels, the willow species and hybrids were classified as resistant, moderately resistant, susceptible or highly susceptible. T. salignus infestation had no effect on the flowering of resistant and moderately resistant willows, but significantly delayed the flowering time, extended the flowering duration, and decreased the catkin length in susceptible species and hybrids. Interestingly, aphid infestation was found to increase the catkin number and total floral output of some willow species and hybrids. It can be concluded that aphid populations and their effects on flowering are host‐specific, with large differences between resistant and susceptible host plants. [ABSTRACT FROM AUTHOR]

The giant willow aphid Tuberolachnus salignus was discovered in New Zealand in late 2013. Despite being a recent addition to the New Zealand fauna, the aphid is already widespread and abundant throughout the country., The giant willow aphid is expected to have negative impacts on host trees, primarily willows ( Salix spp.), as has been observed elsewhere. All willows are exotic to New Zealand and a few have formal weed status, however many species are valued for multiple purposes, including flood protection, land stabilization, shelterbelts, and as early season pollen and nectar resources for honey bees., Tuberolachnus salignus presents a unique problem for New Zealand's thriving honey and honey products industries. Bees readily forage on the vast quantities of honeydew secreted by the aphid, however the honeydew contains melezitose sugar. The low solubility of this sugar results in honey crystallizing in the comb, making it difficult to extract and thereby reducing yield. It is also considered to be poor food for bees, and has been linked to bee dysentery and low overwintering survival., We elaborate on the potential complications for New Zealand as a result of the arrival of this new species and present options for its control and management. [ABSTRACT FROM AUTHOR]

An essay is presented on the design of the Willow Pattern Garden, a Chinese garden located in Hawera, New Zealand. Topics discussed in the essay include the opening of the garden by the Chinese Ambassador to New Zealand in 1968; the use of Chinese porcelain for making decorative designs in blue in the garden; and willow pattern design based on European culture in the garden.

We investigated the effects of invasion by introduced grey willow (Salix cinerea) on beetle communities within four wetland vegetation types: native vegetation, native vegetation following grey willow removal, native vegetation undergoing grey willow invasion and dense grey willow-dominated vegetation. In total, 1505 beetles from 90 species were collected using modified Malaise traps. Native wetland vegetation had significantly lower beetle species richness than willow-dominated vegetation and was dominated by herbivores, whereas detritivores characterised willow-dominated vegetation. Beetle abundance was highest in the willow-dominated vegetation and mostly comprised detritivores. In contrast, beetle abundance was lowest in native wetland vegetation, but had even proportions of herbivores and detritivores. Native wetland vegetation had a high proportion of native beetles present. As grey willows invaded, introduced beetles became more common. The beetle community composition differed significantly between grey willow-dominated vegetation and native wetland vegetation. These compositional differences were mainly due to the increasing complexity of vegetation structure following grey willow invasion. The beetle communities within restored native wetland vegetation were most similar to those within the native wetland vegetation. From a conservation perspective, these results are encouraging and suggest that, although grey willows dramatically alter the composition of beetle communities present, these communities can be restored to a beetle fauna that is similar to those found within native wetland through the removal of the willows. [ABSTRACT FROM AUTHOR]

Abstract: Two indoor feeding experiments with young sheep were conducted to compare effects of feeding condensed tannin (CT) containing willow (Salix spp.) or chaffed lucerne hay (Medicago sativa) upon death of established parasites and parasite fecundity. In Experiment 1, 24 parasite-free weaned male lambs were individually penned, fed chaffed lucerne hay ad libitum for 5 weeks and then fed either lucerne (n =12) or willow (n =12) diets for a further 5 weeks. Twelve days prior to willow feeding, all lambs were infected with a mixed population of 22,300 gastrointestinal nematodes comprising predominantly Teladorsagia spp. (0.93), with the remainder being Trichostrongylus, Cooperia and Haemonchus species. Voluntary feed intake, apparent digestibility, blood composition, faecal nematode egg counts, production of eggs and hatched larvae, female worm fecundity and worm burden at slaughter were measured. In Experiment 2, Teladorsagia eggs were added to the faeces of parasite-free sheep fed either lucerne or willow (n =9) to measure proportional recovery. Recovery of added Teladorsagia eggs was 0.85 in lucerne-fed lambs and 0.53 willow-fed lambs (P<0.001) which were then used as correction factors for Experiment 1 data. Hatched larvae per g of wet faeces tended (P=0.081) to be lower for sheep fed willow than lucerne chaff (0.71 versus 0.83 of eggs added). In Experiment 1, total CT concentration in willow was 27g/kg DM, with only traces in lucerne, while organic matter digestibility was 0.648 versus 0.599 (P<0.001) for willow and chaffed lucerne. Introduction of willow at week 6 reduced VFI (P<0.001) but this progressively increased until it was similar to lucerne-fed sheep during weeks 9 and 10. Feeding willow reduced Haemonchus contortus (P<0.01) and female Teladorsagia circumcinta (P<0.05) worm burdens in the abomasum and reduced Cooperia curticei in the small intestine (P<0.01). Adjusted total daily egg production was lower in willow-fed sheep than lucerne-fed sheep due to reductions for Haemonchus and Teladorsagia spp. (P<0.05). Per capita fecundity (i.e., eggs produced/worm/day) for H. contortus (P<0.05) and the number of eggs in utero as a measure of fecundity in both T. circumcincta and Trichostrongylus spp. (P<0.001) were lower for willow-fed sheep. Faeces incubation revealed reduced production of L3 larvae for both H. contortus and T. circumcincta (P<0.05) in willow-fed sheep. Total white blood cells, total lymphocytes and subsets of lymphocytes were similar for both diets. Feeding willow to parasitised young sheep reduced nematode worm burdens and female worm fecundity, with abomasal dwelling species being most affected and conventional methods of measuring FEC underestimated nematode eggs in the faeces of willow-fed sheep. [Copyright &y& Elsevier]

Abstract: A grazing experiment, conducted for 116 days from 19 January to 15 May in the late summer/autumn of 2006 at Massey University''s Riverside dry-land Farm, near Masterton (New Zealand), compared effects of grazing willow (Salix spp.) fodder blocks or perennial ryegrass (Lolium perenne)/white clover (Trifolium repens) pasture, during the pre-mating and mating periods, on gastrointestinal nematode parasite control and reproductive rates in 7-month old ewe hoggets. A rotational grazing system with 348 weaned Romney ewe hoggets was used, with 116 hoggets per treatment (control pasture with regular anthelmintic drenching, control pasture with trigger drenching and willow fodder blocks with trigger drenching). Hogget live weights (LW), dag scores (DS), faecal nematode egg counts (FEC) and reproductive rates at foetal ultrasound scanning, lambing, tail docking and weaning were measured. Total N concentration (35g/kg dry matter; DM), organic matter digestibility (OMD; 0.68) and metabolisable energy (ME; 10MJ/kgDM) were similar for fodder block pasture and control pasture; the selected tree fodder had lower concentrations of N (24g/kgDM) and was higher in OMD (0.74) and ME (10.4MJ/kgDM). Tree fodder contained higher concentrations of condensed tannins (CT; 22.9g/kg versus 1.6g/kgDM) than control pasture and herbage in willow fodder blocks. Grazing willow fodder blocks increased LW gain (approximately 97g/day versus 86g/day) and increased reproductive rate corrected to equal LW by approximately 17lambs/100 hoggets mated, due to increases in both oestrus activity and conception rates (hoggets pregnant/100 mated). Calculated daily DM (1.41kg) and ME (14MJ) intakes were similar in all groups. Calculated daily CT intake (6.0g versus 2.1g) and CT intake/100g CP intake (2.2g versus 0.7g) were higher for willow fodder block hoggets than for the control pasture groups, and this may have increased the flow of undegraded dietary protein to the small intestine leading to increases in reproductive rates of this group. Grazing willow fodder blocks failed to reduce the number of anthelmintic drenches (3) needed to maintain FEC below 1000eggs/g wet faeces, but was successful in reducing DS compared to grazing conventional ryegrass/white clover pastures. Grazing willow fodder blocks can be beneficial in sustainable farming systems since tree fodder can sustain growth rates, increase reproductive rates and reduce dag formation in parasitized hoggets. [Copyright &y& Elsevier]

New Zealand has hosted three Melampsora species attacking poplars, namely, Melampsora larici-populina, Melampsora medusae and for a single season, Melampsora medusae-populina, a unique interspecific hybrid. The predominant species, Melampsora larici-populina, over-winters via larch and each year new races appear causing defoliation of previously rust-resistant cultivars. Melampsora medusae also occurs in some seasons following over-wintering on certain hosts or by aerial transport from Australia. Willows host four Melampsora species, Melampsora coleosporioides, Melampsora epitea var. epitea and two unidentified species attacking Salix viminalis and Salix daphnoides/Salix incana × open pollinated hybrids, respectively.

The article reports that Glomerella miyabeana was the causal agent of two new diseases that have been observed attacking willows in New Zealand. One and two year-old willows growing in the Aokautere Research Nursery infected with Glomerella miyabeana exhibited stem lesions and leaf spots. Willows in the willow collection kept at the Aokautere Research Nursery were examined closely throughout the growing season for stern lesions, leaf spotting and defoliation. study showed that black stem cankers and leaf spotting and defoliation of willows in New Zealand were caused by the same fungus, Glomerella miyabeana.

The giant willow aphid (Tuberolachnus salignus) is a large stem-feeding insect which forms dense colonies on infested plants. Since T. salignus is a new invasive species in New Zealand, we have a poor understanding of the plant chemical responses to aphid infestation. This study aimed to characterize the volatile organic compounds (VOCs) emissions of fifteen different willow species and hybrids growing in New Zealand, and to evaluate changes in response to T. salignus attack in a field trial. Volatiles were collected using a headspace sampling technique and analysed using gas chromatography-mass spectrometry (GC-MS). We found high variability in the volatile profiles of different species and hybrids, with (Z)-3-hexenyl acetate and (E)-β-ocimene being the only common components to all blends. Taxonomically related plants showed an overlapping pattern of VOC emission, and there seemed to be a clear separation between shrub and tree willows. Responses to aphid infestation were variable, with only four species/hybrids showing changes in their total VOC emission, or that of at least one class of VOCs. A weak positive correlation between aphid population estimates and VOC emissions suggests that responses are species-specific and not infestation-dependent. These results reveal useful information about the interaction between T. salignus and its potential host plants for biological control and pest management purposes. [ABSTRACT FROM AUTHOR]

Mass movement erosion is influenced by land management practices that affect slope hydrology and/or soil strength. Most research on erosion in New Zealand's pastoral farmland has focused on highly erodible North Island hill country with soft or crushed rock geology where space-planted trees (mainly willows and poplars) and afforestation are the most commonly used practices for mitigating against shallow landsliding, gullying, earthflows, and bank erosion. The most common types of mass movement in New Zealand are rapid, shallow slides and flows involving soil and regolith. Individual, mature poplar and willow trees influence the amount of landsliding within a radius of up to 12 m, and the influence of neighbouring trees through intermeshing of roots has also been shown to be important. The degree of slope stabilisation achieved is inversely related to the distance from individual trees and is also dependent on tree ages and the species. Previously quantified reductions in shallow landsliding using 10-m space-planted trees range from 70 to 95 %, but measured or assessed reductions of landsliding are often far less than this because plantings are inadequately spaced and/or poorly maintained.In 1977, a study area at Te Whanga in Wairarapa, New Zealand, was severely impacted by a rainfall event that triggered a large number of shallow landslides. In the 1990s widely-spaced trees were planted at a reasonably high density across the study area in an effort to reduce landslide erosion. We assess the effectiveness of the plantings by mapping landslides in 2010 and 2013/14 orthophotos and spatially relating their locations with those of the fully established trees, accounting for distance from trees and slope gradients. We then hindcast the potential erosion-reducing effect of today's fully established trees for the storm event in 1977, had they already been established by then. The objective is to both quantify the effectiveness of trees and illustrate the importance of targeting the most susceptible locations on slopes when implementing bio-physical mitigation measures. The results can be used to guide future planning and implementation of on-farm measures to reduce rates of landslide erosion and sediment delivery to waterways. [ABSTRACT FROM AUTHOR]