It would take more than just your neighbor developing their land for your land to increase in value. land value taxes calculate the value of the undeveloped land as in land in denser areas is more valuable than suburban land. Unless all of your neighbor are putting up fourplexes changing the entire makeup of the neighborhood, your land value is unlikely to increase. This can't be said of property value where if your neighbor improves their property, your property value and property taxes might increase as a result.