main/trees.json

{
    "type": "category",
    "query": "node[natural=tree];",
    "minZoom": 17,
    "feature": {
        "title": "{{ tags.species|default('Tree') }}",
        "style": {
              "nodeFeature": "CircleMarker",
              "color": "red",
              "fillColor": "red",
              "fillOpacity": 0.1,
              "weight": 1,
              "radius": 6
        },
        "marker": {
            "iconUrl": "img/map_pointer.png",
            "iconSize": [ 25, 42 ],
            "iconAnchor": [ 13, 42 ]
        }
    }
}