SOMEONE has been trying to ruin Paul McCarthy's weekends.

Since early June, usually on Friday mornings or Friday or Saturday nights, about 200 "suspicious" fires have occurred in Boston. McCarthy has the luck to heard the arson squad in a city where a third of all fires are arson-related, and where the fire department is by far the most overworked in the country. One firemen's union official found that to overworked in the country. One firemen's union official found that to bring the force up to the national average of total runs and multiple alarms per engine, the city would have to reopen the 21 stations closed by budget cuts--and then create 34 new companies.

The summer's firestorm, which has finally tapered off in recent weeks, provided Hub firefighters with some memorable nights on the job. On Friday night, August 13, only four buildings were torched--a total of $100,000 in damage, but a total of 32 alarms went off around town, and firemen used every available piece of equipment, including the city's sole fire boat. Charlestown's Engine 50 spent one Saturday night rushing to multiple-alarmers, first two miles to South Boston, then four miles from there to Jamaica Plain, then finally back to Charles town. As for the arson investigators. "We're getting there after the fact." McCarthy admits. "Two or three alarms have gone off by the time the arson squad gets there." In such cases most of any evidence of arson is burned, and very few arrests can be made--only 10 all this summer. For a crime with a roughly two per cent conviction rate, that's not much of a record.

As shocked as Bostonians may be at the epidemic of torching, they should final its caused even more troubling. If it were just the word of a few firebugs or linked to a general increase in crime, one would expect the arson to have centered on the city's most crime-ridden area, Roxbury--especially on hearing that vacant buildings, a common commodity there, were the targets of 70 percent of the fires. (The figures is the main reason the arson took no lives.)

But instead, most of the fires hit areas generally considered more "desirable" locales: neighborhoods on the rebound, with rising real estate markets, active renovation of picturesque old homes, as well as relatively little crime and--in certain cases--healthy racial integration Jamaica Plain and Mattapan in particular, as well as the South End, South Boston and others, all have recently been attracting young, "upscale" professionals with an interest in improving their new neighborhoods. Meanwhile, an unprecedented number of their buildings have been torched.

IT'S DIFFICULT for many people to accept the notion that rehabilitation, or "gentrification" as it's commonly called, of moribund neighborhoods can be anything but an unqualified boon to the area. Those people include, for example, Boston Mayor Kevin H. White, who's convinced it's "a good thing that richer, professional people are moving in, buying condos. Most neighborhoods are whipped right now." To Mayor White, the implication that gentrification could have ill side-effects is outrageous; after Time magazine ran a picture of a burned-out office building "in gentrifying Jamaica plain" he called the photo "a disgrace."

But the key to remember is that when "richer, professional people" move into Jamaica Plain or the South End, someone else has to leave. And though White may see South Boston and Mattapan as "whipped neighborhoods," at least they've been home for people who couldn't afford Back Bay or the suburbs.

So when a neighborhood's real estate potential skyrockets, landlords look for a way to get the current residents out and the wealthier residents--who can pay higher rents or higher condominium prices--in. And there's no doubt that many landlords are unscrupulous enough to use arson to chase residents out. An extreme instance of such tactics was the 1979-80 string of condo conversions in already-high-rent areas, which was apparently responsible for a fourfold increase in Back Bay's arson rate, scaring off many renters who had resisted conversion.

Now that several other neighborhoods around the city are on the verge of their own little real estate booms, arson is again pushing the old residents out. Either landlord are engaging in blatant arson-for profit or they're cutting maintenance to their buildings, which pressures tenants to abandon the apartments. After that, vandals may torch the building, or scavengers, called "junkies" in the arson business, strip the building for pipes or scrap metal and burn what's left to cover up the robbery. There are between 1200 and 1400 vacant buildings in Boston; once they are disposed of--as about 170 were this summer--the real estate market opens up for redevelopment.

The matter of gentrification also has implications for Boston's racial integration problems. Usually, integration in housing occurs after some minority families move into a previously all-white neighborhood; the whites often then start to flee the area. But in Jamaica Plain, for instance, it's been the white professionals who are moving in, pushing minority residents out. So while that area is well-integrated on paper (roughly) half white, half Black or Hispanic), the rents that have risen as much as 70 percent in three years have pushed the minorities, Blacks in particular, away from the center of the Jamaica Plain neighborhood. Most have ended up on the neighborhood's northwest fringe, not too far from the edges of Roxbury, Boston's Black ghetto. The Black residents are simply being compressed into smaller areas; according to MIT urban studies professor Yohel Camayd-Freixas, the central Jamaica Plain area averages two or three persons per hours, in contrast to twelve in the mostly Black section.

GENTRIFICATION raises a myriad of further questions, including whether City Hall purposely cuts fire protection to areas eyed by property developers to hasten resident turnover--as was charged in New York by some arson-watchers after a similar wave in 1972 But in the meantime, while city officials debate what to do with all the vacant buildings still dotting the map, or how to beef up the arson squad to catch the culprits, they might do well to think a little more thoroughly about the fate of Boston's changing neighborhoods, and how to enable poorer long-term residents to stay put in their homes.

Civic boosters take pride in a healthy real estate market; it's great for Boston's image as "the livable city"--Mayor White's phrase. But if the cost of livability includes millions of dollars in fire damage and the title of America's arson capital--and the social pressures that title implies--Bostonians had better ask themselves if they can really afford it.