Eucalyptus are prone to attack by a range of insects. Spacing between trees should be 3 to 4 m. Species that may be suitable are listed in Table 1 . All are moderate to fast growing and respond well to intensive management and side trimming. Deciduous trees provide less wind protection during the winter months. This is a disadvantage for annual vegetable cropping and evergreen perennial crops.
Poplar rust affects poplars, though some species are resistant.
Willows are a host for the carrot aphid, which is a pest of carrots, parsnips and celery. This tree is fast growing and reaches a height of 15 to 20 m. Pines are suitable for planting as windbreaks on horticultural properties though they have some limitations. Older radiata trees become too open at their base and often require an under planting of a shade tolerant, lower growing species. This lower growing species should be planted at the same time as the pines. Other problems with radiata trees include a canopy which is too dense when young, too wide a circumference when older and a poor ability to form a hedge.