If Acorn reporter Carissa Marsh's seven-part series "Rethinking Simi Valley" has taught us anything, it's that density matters.

Of all the different issues Marsh's reporting has brought to light, none has generated a more passionate discourse among residents than the rezoning of land parcels for higher density, a move the city might have to make to alleviate its shortage of housing.

Scientifically speaking, density is an exact measure of how tightly packed a certain amount of matter is. But the density associated with city planning—which defines how many dwelling units are permissible to be built per acre of land available—carries a different complexity.

In Simi, density is at the heart of the growth debate. Some residents fear that if the population per acre continues to increase, nothing will remain of the small-town character that so many of us hold dear. Others are encouraging growth, noting that with development comes revenue and a larger tax base with which to pay for city services.

There seem to be two sides to this argument: Those who don't like the idea of increasing density, but see it as necessary, and those who don't like the idea of increasing density, period.

But Simi Valley is required by the state to show it has the "potential" to build 3,735 dwelling units by the year 2014, a number determined last year by the Southern California Council of Governments housing needs assessment.

Simi can't achieve that number using available undeveloped land because, quite simply, very little of it now exists in the city.

So without building into the beloved hills that surround us, the city is forced to make the tough decision to do more with the parcels that are already in use by increasing the density so more dwellings can fit in the same amount space.

As the General Plan update marches on, density, and how to deal with it, is sure to be a hot-button topic.

Where do you stand on increasing density? And how would you deal with this dilemma if you were in charge?

One thing is certain. Opponents like those living in the rural neighborhoods identified as potential targets for increased density are going to have to come to terms with the fact that city leaders can't simply turn on the "No Vacancy" sign and go to bed.

That's just dense.