Too many nature_reserve at zoom 10

[nvkelso]

• What did you see? I can see POIs at zoom 10, when the landuse sibling isn't visible until much later.
• What did you expect to see? Probably just do what the polygon is doing.
• What map location are you having problems with?

• https://tangrams.github.io/explorer/#10.0/42.3961/-71.1365/kind/nature_reserve
• https://tangrams.github.io/explorer/#10.0/51.4352/0.0492/kind/nature_reserve

• Screenshot? Props for animated gifs.

[nvkelso]

Related to: #1609

[nvkelso]

QA verified.