I have planted Lyonothamnus right along the coast, and they can be abit fickle and variable in vigor in high wind situations. I would agree that they are probably best with some shelter from wind, rather than full force exposure. You might also consider some smaller wind tolerant evergreen trees such as Tristaniopsis laurina, or the taller growing Cow Itch Tree, Lagunaria pattersonii. The Agonis flexuosa and the dark form cultivar already mentioned could also be good. If you are planting these in a lawn situation, the Mayten tree would still be a good choice, as even with root sprouting, in a lawn, with regular mowing, this wouldn't be an issue. Another classic tree for coastal windy conditions would be some of the Leptospermums or Melaleucas, much used along the coast both north and south. Another classic tree for coastal wind is the New Zealand Christmas Tree, Metrosideros excelsa. I have also planted the South African Silver Tree, Leucadendron argenteum 3 blocks from the beach in Moss Beach, and they are thriving, but this can also be either a short lived or temperamental tree. In any case, regardless of what you plant, you will probably be better off if you plant it out as a 5 gallon sized tree, and make sure that it is not at all root bound or any kinked roots at time of planting, and stake it so that the trunk can move with the wind, thereby greatly increasing the rooting ability to withstand winds. Even your first choice of Eucalyptus polyanthemos might have been successful if thinned occasionally while young, or even headed back to allow regrowth as a multi trunk specimen. I am willing to bet it had kinked or encircling roots that made it structurally unsound from the start. Other Eucalyptus species to consider might also include E. ficifolia, E. pulverulenta or E. perriniana. Smaller growing pines such as the Shore Pine, Pinus contorta or Pinus muricata might also be considerations. Post again and let us know what you decided to plant, okay?

Here's some more good, smallish evergreen blooming trees: Acacia baileyana BAILEY ACACIA Acacia cognata/subporosa RIVER WATTLE Acacia podalyriifolia PEARL ACACIA Acca (Feijoa) sellowiana PINEAPPLE GUAVA Arbutus unedo STRAWBERRY TREE Bauhinia forficata BRAZILIAN ORCHID TREE Callistemon citrinus (standrad) LEMON BOTTLEBRUSH Ceanothus arboreus (standard) TREE CEANOTHUS Escallonia x exoniensis ÂBalfouri ESCALLONIA Escallonia laevis PINK ESCALLONIA Eucalyptus caesia GUNGURRU Eucalyptus torquata CORAL GUM Eucalyptus torquata CORAL GUM Garrya elliptica SILKTASSEL Leptospermum scoparium (larger cultivars) NEW ZEALAND TEA TREE Melaleuca nesophila PINK MELALEUCA Nerium oleander (standard) OLEANDER Pittosporum brevicalyx CHINESE PITTOSPORUM Psidium cattleianum STRAWBERRY GUAVA Rhaphiolepis ÂMajestic Beauty M. B. INDIAN HAWTHORNE Tecoma stans YELLOW BELLS By the way, a 15-25-foot tree is a TEENY-TINY. The above includes (mostly?) large shrubs that can be pruned up to look like a tree ("standards" and otherwise). Joe

You are on the right track with the ideas that (1) you want a hedge that is somewhat permeable to allow the break to baffle the wind and (2) you want two rows in the planting to better direct the wind up and WAY over. I suggest the windward, lower row could be: Cistus x skanbergii HYBRID ROCK ROSE Leptospermum scoparium NEW ZEALAND TEA TREE Westringia fruticosa COAST ROSEMARY And the leeward, taller row could be: Cupressus arizonica ARIZONA CYPRESS Lavatera assurgentiflora TREE MALLOW Leptospermum laevigatum AUSTRALIAN TEA TREE Melaleuca nesophila WESTERN TEA MYRTLE Melaleuca styphelioides BLACK TEA TREE Pittosporum crassifolium KARO Joe

There aren't a lot of truly "dwarf trees". You say you don't want a "bush or shrub" but your limit of 15 feet pretty much rules out true trees (which many botanists say start at 20 feet) and leaves you with the opportunity to take a tall-growing shrub and train it to look like a tree. Shrubs trained as such -- single trunk with a crown -- are called "standards". Usually marketed as "patio trees". Here's a few ideas: Acca (Feijoa) sellowiana PINEAPPLE GUAVA Banksia ashbyi ASHBY'S BANKSIA Banksia coccinea SCARLET BANKSIA Ceanothus arboreus 'Blue Mist', 'Cliff Schmidt', 'Thundercloud', 'Trewithen Blue' TREE CEANOTHUS Ceanothus thyrsiflorus 'Snow Flurry' SNOW FLURRY CEANOTHUS Cercocarpus betuloides MOUNTAIN IRONWOOD Comarostaphylis diversifolia SUMMER HOLLY Cotinus coggygria SMOKETREE Escallonia laevis PINK ESCALLONIA Escallonia x exoniensis 'Balfouri', 'Frades' HYBRID ESCALLONIA Grevillea 'Honeygem', 'Ivanhoe', 'Long John', 'Poorinda Blondie', 'Red Hooks' HYBRID GREVILLEA Leptospermum lanigerum WOOLY TEA TREE Leptospermum polygalifolium 'Yarra River' RED SPIRE TEA TREE Melaleuca decussata LILAC MELALEUCA Melaleuca elliptica GRANITE BOTTLEBRUSH Osmanthus fragrans SWEET OLIVE Pittosporum crassifolium KARO Pittosporum eugenioides TARATA Pittosporum tenuifolium KOHUHU, TAWHIWI Psidium cattleianum STRAWBERRY GUAVA Rhaphiolepis 'Majestic Beauty' M. B. INDIAN HAWTHORNE All of these need some work (pruning) to make them look like a tree (single trunk, crown). Some more than others (as already pointed out with Cercis occidentalis). You didn't say why you need it to top out at 15 feet. Are there utility wires or a view from the house or? Joe